CP: AJAX Erros in Backend

When I do any change (assign a Instructor or change content) and click on Update, I get this error in the console (Google Chrome).

app.js:25 Uncaught TypeError: Cannot read property 'value' of null
https://waketo.de/wp-admin/admin-ajax.php Failed to load resource: the server responded with a status of 500 ()

In Firefox I get this,
POST https://waketo.de/wp-admin/admin-ajax.php

500 Internal Server Error

  • Bojan Radonic
    • Head of Support

    Hey there Sebastian Seefried,

    Hope you're well today :slight_smile:

    Internal server errors are caused in most cases by plugin conflicts or lack of PHP memory on your server for example.

    I'd suggest testing testing for a conflict first, this means temporarily switching to one of the default themes (like TwentyFifteen or even CoursePress theme in your case) and also deactivating plugins one by one to see which one is causing this, if any. You can follow the flowchart on this link https://premium.wpmudev.org/manuals/using-wpmu-dev/getting-support/.

    Let me know if you find anything so we can see how to proceed with this :slight_smile:


  • Sebastian Seefried
    • Flash Drive


    Yesterday we got an PHP 7 update, as well we have enabled our hosting's cache (CDN + Page).

    The only improvement was that when I click update, a new message appears "Updated" the icon is green,

    BUT it is still not updated? Is there a way to remove this AJAX story?

    P.P. On our dev instance, I have removed ALL plugins (incl. WooCommerce and WPMU) and used TwentySixteen. Same story.

  • Bojan Radonic
    • Head of Support

    Hey there Sebastian Seefried,

    Now that you've mentioned PHP 7, I've tested that on my sandbox site to see if I'll get some errors but I didn't get anything similar, this could be related to PHP version so if you can test that on your development site by switching to 5.5 or 5.6.

    As for the cache I don't believe that should be the case since as far as I know admin pages are not cached so I don't believe that can be the issue, it could potentially cause JS errors so it would be worth testing without that as well.

    If neither really help what you can do is send us your FTP details for your development site so we can take a closer look. You can end us your details through our contact form https://premium.wpmudev.org/contact/ using this template:

    Subject: "Attn: Bojan"
    -WordPress admin username
    -WordPress admin password
    -login url
    -FTP credentials (host/username/password)
    -link back to this thread for reference
    -any other relevant urls

    Select "I have a different question" for your topic - this and the subject line ensure that it gets assigned to me :slight_smile:

    Best regards,

  • Sebastian Seefried
    • Flash Drive

    Hi Bojan,

    It is not PHP since we have this issue for more than a month (with PHP 5.6) and we still have it with the new PHP 7. I am not sure how the plugin is written/code that's why I think the best approach is someone to have a look. I also have a dev working instance, where it does not work as well. I will share you the details for the DEV.

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