why i cannot upload the zip file in CPanel it says "The upload failed. The server indicated HTTP error 500 (internal error)" what does it mean

Hello there, I recently worked on a Joomla theme but I get an error when uploading it to my host . The error is as follows: This page isn’t working ( URL) is currently unable to handle this...

I have the same problem. I have this problem after page or section update. I cannot update the changes I have made. I have the same issue when exporting after saving the update on the desktop version....