Any time you encounter a 500 error, the first thing we recommend doing is
checking the web server's error logs for more information.
In many cases, the job scheduler is the issue, and restarting it will often resolve the problem. If the job scheduler has stopped running for some reason, this can lead to a 500 error during many operations.
Please see the following thread for further details on checking the error logs, restarting the job scheduler, and if those steps fail, some other common maintenance tasks that can be useful in resolving issues:
If you try all of the recommendations in that thread and it still does not resolve the 500 error, please share any relevant message you find in the webserver logs, as well as more information about your installation environment (AtoM version; whether you followed the recommend installation instructions or made changes, etc) and we will try to provide further suggestions.
Cheers,