Installing and upgrading help

Have you any non core plugins or themes installed? If you have, get rid of them and see if it helps.

Failing that...  

- switch on Debugging. You may have to do this by copying lines from config-dist.php to config.php
- check your web server's error log
- switch on the Javascript Console in your browser and reproduce the error. Are there any JS errors (in red)

When one of my sites had this error, it was because students were using an old non-secure HTTP link to access a page in a course, which conflicted with the secure HTTPS link to FontAwesome that our Boost theme used.

If you're using Boost or another default Moodle theme that uses FontAwesome icons (e.g. in the menu bar), you'll need to encrypt your site with an SSL certificate and forward all HTTP traffic to HTTPS.

We had the same issue when we upgrade from PHP 5.6.36 to PHP 7.1.22.  I was seeing a lot of Zend Opache error messages in the event logs, which I think is the error for this popup. The last line in the code below is what really fixed the issue - after that one change, no more errors in logs and no more popups. Hope this helps!

Here's what seems to have fixed the issue  - In the php.ini file: 

·         opcache.enable=1

·         zend_extension="C:\Program Files (x86)\Parallels\Plesk\Additional\PleskPHP70\ext\php_opcache.dll"  ***THIS IS JUST THE CODE EXAMPLE-OUR PATH WAS DIFFERENT***

·          

·         opcache.memory_consumption = 128

·         opcache.max_accelerated_files = 4000

·         opcache.revalidate_freq = 60

·          

·         ; Required for Moodle

·         opcache.use_cwd = 1

·         opcache.validate_timestamps = 1

·         opcache.save_comments = 1

·         opcache.enable_file_override = 0

·         opcache.revalidate_path = 1 ; May fix problems with include paths

·         opcache.mmap_base = 0x20000000 ; (Windows only) fix OPcache crashes with event id 487