Thank you for your question. If you are getting Internal Server, and 404 errors, it is often related to Folder permissions, or something within the .htaccess file is interfering with the site loading.
I found this information on the Official Joomla Forum, I recommend reading that forum post, as it provides several solutions.
If you have any further questions, feel free to post them below.
I rename all .htaccess file of all joomla sites. Public_html and joomla folders are 750 , but all remaining folder under public_html are 755, all files are 644. Some folders in my root directory , that are outside the public_html are 700 and files are 600. Should I change these file permission to 755 and 644 ?
I change the public_html permisson to 755 . After all done, the issue is not solved. My problem is only cannot install new extension at all my joomla sites suddenly. These are running well for years or months and still running well. But cannot add new extensions.
Thanks for your suggestion.
Sorry to hear you are getting an Internal Server Error.
The previous individual stated that they contacted their host for an issue so unfortunately, we are unsure of the outcome.
As sttated previousl by John-Paul, this can be cause by folder permissions issues or within your .htaccess file. Try renaming your .htaccess file and checking your folder permissions for narrow down what in particular may be causing the issue.
Yes. I had to submit InMotion ( from AMP log in) for restore from their server. I get back my site although I lost some client data because the last back up can store was about one month late. Anyway I give many thanks to InMotion support.