Failed Ajax request or invalid JSON returned on Editorial History (OJS 3.1.0-1)

I get a “Failed Ajax request or invalid JSON returned” pop up when trying to look at the editorial history of a submission. My error log shows nothing to do with this, but I get this in the developer tools:

GET https://ijpds.org/$$$call$$$/information-center/submission-information-center/view-information-center?submissionId=444&_=1512736305619 500 (Internal Server Error)
send @ jquery.min.js:4
ajax @ jquery.min.js:4
a.fn.pkpAjaxHtml @ pkp.min.js:443
a.pkp.controllers.modal.AjaxModalHandler.modalOpen @ pkp.min.js:327
a.pkp.controllers.modal.ModalHandler @ pkp.min.js:314
a.pkp.classes.ObjectProxy.parent @ pkp.min.js:119
a.pkp.controllers.modal.AjaxModalHandler @ pkp.min.js:326
a.pkp.classes.ObjectProxy.parent @ pkp.min.js:119
a @ pkp.min.js:117
a.pkp.classes.Helper.objectFactory @ pkp.min.js:116
(anonymous) @ pkp.min.js:443
each @ jquery.min.js:2
each @ jquery.min.js:2
a.fn.pkpHandler @ pkp.min.js:443
a.pkp.classes.linkAction.ModalRequest.activate @ pkp.min.js:141
a.pkp.controllers.linkAction.LinkActionHandler.activateAction @ pkp.min.js:336
a.pkp.classes.Handler.handleEvent @ pkp.min.js:124
dispatch @ jquery.min.js:3
r.handle @ jquery.min.js:3

There’s also this warning:
jquery.min.js:4 [Deprecation] Synchronous XMLHttpRequest on the main thread is deprecated because of its detrimental effects to the end user’s experience. For more help, check https://xhr.spec.whatwg.org/.
send @ jquery.min.js:4
ajax @ jquery.min.js:4
a.pkp.controllers.NotificationHandler.fetchNotificationHandler_ @ pkp.min.js:227
a.pkp.classes.Handler.handleEvent @ pkp.min.js:124
dispatch @ jquery.min.js:3
r.handle @ jquery.min.js:3
trigger @ jquery.min.js:3
triggerHandler @ jquery.min.js:3
a.pkp.controllers.NotificationHandler @ pkp.min.js:226
a.pkp.classes.ObjectProxy.parent @ pkp.min.js:119
a @ pkp.min.js:117
a.pkp.classes.Helper.objectFactory @ pkp.min.js:116
(anonymous) @ pkp.min.js:443
each @ jquery.min.js:2
each @ jquery.min.js:2
a.fn.pkpHandler @ pkp.min.js:443
(anonymous) @ 3:166
j @ jquery.min.js:2
fireWith @ jquery.min.js:2
ready @ jquery.min.js:2
K @ jquery.min.js:2

I’ve tried clearing my cache, but that didn’t do anything.

The error seems to be something to do with this:
PHP Fatal error: Call to undefined method InformationCenterHandler::InformationCenterHandler() in /var/www/html/lib/pkp/controllers/informationCenter/PKPSubmissionInformationCenterHandler.inc.php on line 25

This file wasn’t in previous versions

Hi @mickbale,

Are you sure you’re running a clean OJS 3.1.0-1 installation? That file (lib/pkp/controllers/informationCenter/PKPSubmissionInformationCenterHandler.inc.php) doesn’t exist in OJS 3.1.0-1.

Regards,
Alec Smecher
Public Knowledge Project Team

Yea just solved this by reinstalling it again. Thanks for your help