iam using OJS 3.1.1. with php7.1 the page of plugin gallery see as empty no any plugin found
the error log :
[Sun Jul 15 09:01:38.825293 2018] [mpm_prefork:notice] [pid 1538] AH00169: caught SIGTERM, shutting down
[Sun Jul 15 09:01:40.408557 2018] [mpm_prefork:notice] [pid 2804] AH00163: Apache/2.4.18 (Ubuntu) configured – resuming normal operations
[Sun Jul 15 09:01:40.408620 2018] [core:notice] [pid 2804] AH00094: Command line: ‘/usr/sbin/apache2’
[Sun Jul 15 09:01:52.695510 2018] [php7:warn] [pid 2807] [client 10.5.33.34:35850] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/settings
[Sun Jul 15 09:01:53.157302 2018] [php7:warn] [pid 2807] [client 10.5.33.34:35850] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index
[Sun Jul 15 09:01:58.903532 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index
[Sun Jul 15 09:01:59.048652 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/index
[Sun Jul 15 09:01:59.272714 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/index
[Sun Jul 15 09:01:59.759975 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/index
[Sun Jul 15 09:01:59.816601 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/index
[Sun Jul 15 09:02:02.522783 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/index/admin/index
[Sun Jul 15 09:02:02.901589 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.057564 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.079123 2018] [php7:warn] [pid 2811] [client 10.5.33.34:35865] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.093866 2018] [php7:warn] [pid 2815] [client 10.5.33.34:35872] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.099974 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.121024 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:03.240284 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:07.149146 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/submissions
[Sun Jul 15 09:02:07.365259 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.381429 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.411405 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of ContextSettingsForm::fetch($request, $params = NULL) should be compatible with Form::fetch($request, $template = NULL, $display = false) in /var/www/html/ojs/lib/pkp/classes/controllers/tab/settings/form/ContextSettingsForm.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.411422 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of ContextSettingsForm::initData($request) should be compatible with Form::initData() in /var/www/html/ojs/lib/pkp/classes/controllers/tab/settings/form/ContextSettingsForm.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.411428 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of ContextSettingsForm::readInputData($request) should be compatible with Form::readInputData() in /var/www/html/ojs/lib/pkp/classes/controllers/tab/settings/form/ContextSettingsForm.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.411434 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of ContextSettingsForm::execute($request) should be compatible with Form::execute() in /var/www/html/ojs/lib/pkp/classes/controllers/tab/settings/form/ContextSettingsForm.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.411442 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPAppearanceForm::fetch($request) should be compatible with ContextSettingsForm::fetch($request, $params = NULL) in /var/www/html/ojs/lib/pkp/controllers/tab/settings/appearance/form/PKPAppearanceForm.inc.php on line 18, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.429494 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.641556 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.685626 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.728022 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:07.733514 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of BlockPluginsListbuilderHandler::initialize($request) should be compatible with MultipleListsListbuilderHandler::initialize($request, $args = NULL) in /var/www/html/ojs/lib/pkp/controllers/listbuilder/settings/BlockPluginsListbuilderHandler.inc.php on line 17, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.430657 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.497848 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.501109 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.504815 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of CategoryGridHandler::doSpecificFetchGridActions($args, $request, &$templateMgr) should be compatible with GridHandler::doSpecificFetchGridActions($args, $request, $templateMgr) in /var/www/html/ojs/lib/pkp/classes/controllers/grid/CategoryGridHandler.inc.php on line 0, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.543666 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of UploadPluginForm::fetch($request) should be compatible with Form::fetch($request, $template = NULL, $display = false) in /var/www/html/ojs/lib/pkp/controllers/grid/plugins/form/UploadPluginForm.inc.php on line 22, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.543681 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of UploadPluginForm::execute($request) should be compatible with Form::execute() in /var/www/html/ojs/lib/pkp/controllers/grid/plugins/form/UploadPluginForm.inc.php on line 22, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.550305 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PluginGridHandler::initialize($request) should be compatible with CategoryGridHandler::initialize($request, $args = NULL) in /var/www/html/ojs/lib/pkp/classes/controllers/grid/plugins/PluginGridHandler.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.550319 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of PluginGridHandler::loadCategoryData($request, &$categoryDataElement, $filter) should be compatible with CategoryGridHandler::loadCategoryData($request, &$categoryDataElement, $filter = NULL) in /var/www/html/ojs/lib/pkp/classes/controllers/grid/plugins/PluginGridHandler.inc.php on line 20, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:09.550337 2018] [php7:warn] [pid 2814] [client 10.5.33.34:35871] PHP Warning: Declaration of SettingsPluginGridHandler::loadCategoryData($request, $categoryDataElement, $filter) should be compatible with PluginGridHandler::loadCategoryData($request, &$categoryDataElement, $filter) in /var/www/html/ojs/controllers/grid/settings/plugins/SettingsPluginGridHandler.inc.php on line 18, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:49.649241 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: fsockopen(): php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution in /var/www/html/ojs/lib/pkp/classes/file/wrappers/HTTPFileWrapper.inc.php on line 77, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:49.649286 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: fsockopen(): unable to connect to ssl://pkp.sfu.ca:443 (php_network_getaddresses: getaddrinfo failed: Temporary failure in name resolution) in /var/www/html/ojs/lib/pkp/classes/file/wrappers/HTTPFileWrapper.inc.php on line 77, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:02:49.649313 2018] [php7:warn] [pid 2810] [client 10.5.33.34:35864] PHP Warning: DOMDocument::loadXML(): Empty string supplied as input in /var/www/html/ojs/lib/pkp/classes/plugins/PluginGalleryDAO.inc.php on line 57, referer: http://localhost/ojs/index.php/ABC/management/settings/website
[Sun Jul 15 09:12:06.846515 2018] [php7:warn] [pid 2816] [client 127.0.0.1:44124] PHP Warning: Declaration of PKPUsageEventPlugin::getEnabled() should be compatible with LazyLoadPlugin::getEnabled($contextId = NULL) in /var/www/html/ojs/lib/pkp/plugins/generic/usageEvent/PKPUsageEventPlugin.inc.php on line 0