WordPress error 500 is related to the server error. In case, if you encounter with 500 internal server error, try these troubleshooting steps
.Refresh the URL that you have requested. The error may be for the short term.
Clear all the website cache from your web browser
Delete website cookies because error 500 can be obstructed by clearing the website cookies. Restart your web browser after clearing cookies.
Interact with your WordPress developer or web host for more help.
Create a new .htaccess file. Sometimes the incorrect code and command in .htaccess file cause error 500 on the website. Rename the file with another name; it will automatically become invalid. Then create a new .htaccess file and upload it to the server.