A small number of Thrive Content Builder and Thrive Leads Users may experience the "endless loading spinner" when trying to save. This is an unfortunate consequence of certain security plugins or server configuration settings.
1. Check What's Causing the Error
If this should ever happen to you, the first step to take is to hit f12 on your keyboard. This will load a set of options at the bottom of your browser. Then, you should click on "Console":
You will then be able to see whether there are any errors. Here is what an internal server error looks like:
Now you have confirmed that the problem is caused by an internal server error.
2. How to Solve the Internal Server Error 500 Issue
There are two primary causes for internal server errors when using our software:
Security restrictions - in order for data to be saved, our software needs to communicate with a WordPress file called admin-ajax.php. Some security plugins and server configurations restrict access to this file, causing an internal server error.
Fix - Disable any security plugins temporarily and test again. This will isolate the issue. Make sure that the yoursite.com/admin-ajax.php file is not blocked and is fully reachable.
The request is too big - servers have settings that limit the size of data that can be sent to them in a request. Sometimes, if you're building a big piece of content, this limit may be breached causing an internal server error.
Fix - ask your host to increase one/all of the following limitations:-
If the request is too large for the server then you will commonly see an error like this:-
"[Wed Aug 19 11:15:50 2015] [warn] [client 126.96.36.199] mod_fcgid: HTTP request length 131215 (so far) exceeds MaxRequestLen (131072), referer: http://yourdomain.com/?page_id=11913&tve=true"
This particular error message shows that the size of the HTTP request length was too big for the server configuration, and that's what was causing the error.
If you're still encountering issues, and the endless spinner is still persisting, please also check out this article, which provides some more situations and issues that might cause the endless loading screen to appear.