Hi,
I get an error in the plugins, when trying to generate the report from PKP Usage statistics report, a page with a 500 error appears, and in the php logs, the following error is displayed:
[Fri Sep 18 20:34:11.617139 2020] [php7:error] [pid 9112] [client 172.20.0.152:51456] PHP Fatal error: Uncaught Error: [] operator not supported for strings in /var/www/html/xxxxxxxx/classes/statistics/MetricsDAO.inc.php:34\nStack trace:\n#0 /var/www/html/xxxxxxxx/plugins/generic/usageStats/PKPUsageStatsReportPlugin.inc.php(84): MetricsDAO->getMetrics('ojs::counter', Array, 'a:1:{s:10:"cont...', 'a:1:{s:5:"month...', NULL)\n#1 /var/www/html/xxxxxxxx/plugins/generic/usageStats/OJSUsageStatsReportPlugin.inc.php(32): PKPUsageStatsReportPlugin->getMetrics('ojs::counter', Array, 'a:1:{s:10:"cont...', 'a:1:{s:5:"month...', NULL)\n#2 /var/www/html/xxxxxxxx/lib/pkp/pages/management/PKPToolsHandler.inc.php(208): OJSUsageStatsReportPlugin->getMetrics('ojs::counter', Array, 'a:1:{s:10:"cont...', 'a:1:{s:5:"month...')\n#3 /var/www/html/xxxxxxxx/lib/pkp/pages/management/PKPToolsHandler.inc.php(64): PKPToolsHandler->generateReport(Array, Object(Request))\n#4 /var/www/html/xxxxxxxx/lib/pkp/classes/core/PKPRouter.inc.php(390): PKPT in /var/www/html/xxxxxxxx/classes/statistics/MetricsDAO.inc.php on line 34, referer: