Have you just got a Moodle JSON error while trying to upload files?

Usually, this invalid JSON string indicates an upload error.

This can occur due to reasons like outdated browsers, larger file size, improper file format, etc.

At Bobcares, we often get requests to fix Moodle errors, as a part of our Server Management Services.

Today, let’s see how our Support Engineers fix this JSON error.

How we debug JSON error in Moodle?

Moodle is one of the popular Learning Management Systems. This helps in managing courses and support learning.

It has features for easy upload and download of study materials. Also, it supports many file formats.

Fortunately, Moodle has a debug feature in its admin panel. So, whenever a Moodle error pops up, our Support Engineers turn the debug option ON.

Firstly, we login as an admin. Then navigate as, Administration >> Site administration >> Development >> Debugging. Also, the drop-down list shows various options regarding the Debug messages.

So, debugging gives a more clear picture of the error. After knowing this fixing the error is relatively easy.

Causes and fixes for the Moodle JSON error?

Moodle shows JSON error due to outdated browsers, file upload errors, etc. The typical error message when a user tries to upload a file in moodle appear as,

Let’s have a deeper look at each reason.

1. Failed file upload in Moodle

In many situations, a failed file upload shows JSON error. Usually, this happens when Moodle doesn’t support that particular file format or improper file name.

If the error is with the file format, then we can add it in admin settings. For this our Support Engineers navigate as Site administration >> Server >> File types. Here we add a new file type and save the settings.

Similarly, special characters in the file name can result in a failed upload. Because Moodle fails to identify these characters. So, we check the file name and ask the user to change it if needed.

2. Server-side restrictions

Sometimes server settings can also restrict file upload. So, we check the server logs. If this is showing errors on any server settings, we try disabling it. For instance, mod_security may restrict file upload.

Or else, if the file size is larger, we check the maximum file upload size in the server. Later, we increase it if needed. We check all the settings that restrict file upload in the server, like PHP settings. This includes post_max size, upload_max_filesize, etc.

3. An outdated browser version

Moodle keeps on updating the software to include new features. As we access Moodle mostly via a browser, it’s important to have an updated browser.

Outdated browsers cannot identify some file formats. This can lead Moodle users to end up with the invalid JSON string error. So our Support Engineers always recommend customers to update their browser versions.

Similarly, cookies and temporary data in the browser can lead to this error. Hence, we ask customers to clear cookies and browsing data. Thereafter reloading the page may fix the error.

[Still having trouble in fixing Moodle errors? – We’ll help you.]

Conclusion

In short, Moodle JSON error occurs due to file upload errors, outdated browsers, etc. Today, we saw how our Support Engineers fix this error for our customers.