Akeeba Backup does not load in the frontend of your site. A couple of replies ago you were convinced this was the problem even though I told you it's not the case. Between the two of us only one has been developing and doing support for this software for 15 years and knows how servers work. But we'll get back to that later.
Your newest arbitrary assumption is just as wrong as all of the previous ones. Admin Tools' Repaid and Optimize ables, as documented, only asks your database server to run the commands literally called REPAIR TABLE and OPTIMIZE TABLE. These do NOT have anything to do at all with your site's static files.
If you actually read my replies and used common sense you would not be wasting your time and my time.
I already told you that I could see that you were getting a 404 Not Found error for the CSS and JavaScript static files. This means that the actual URLs generated by your PHP code are correct but something on your web server, not PHP, prevents them from loading.
What you are focusing on is 100% on the PHP side of your site which has nothing at all to do with your problem.
Getting a 404 on a static file whose path I checked and coincides with what is should be for the Cassiopeia template tells me that it can be exactly one of the following problems:
1. The file is legitimately not there.
2. The file is blocked either by a .htaccess rule or by wrong ownership/permissions. Now, you say, this should be a 403 Forbidden, not a 404 Not Found. Yes, but if your server is configured to have custom error pages (default in cPanel) and these custom error page files do not exist (also default in cPanel!) you get a 404 instead.
I asked you to replace the .htaccess because it's the easiest of the three checks we have to do in this case. You have already proven it's not the .htaccess. Therefore it's not something generated by Admin Tools. Akeeba Backup doesn't touch this file except in the context of a restoration and ONLY if you tell it so; this wasn't the case so scratch that too.
The next step is checking whether the files are there and can be read at all (the latter tested by downloading them and checking if their contents are non–empty). Yeah, yeah, you didn't delete them. However, we've seen servers screwing up and deleting files or making them inaccessible when the filesystem is very full and/or corrupt and you try to write a bunch of files, like what happens when Joomla installs an extension! This would explain why you say that the problem happened immediately after installing Akeeba Backup — even though I have my reservations about whether your recollection of “immediately after” is accurate.
If this is not the case we have debunked the “immediately after installation” claim and we are left with the final possibility: ownership and permissions. Did you run Fix Permissions in Admin Tools? Depending on the ownership of your files and the permissions you chose to apply it may have resulted in rendering your static files inaccessible. Remember that PHP and the web server process may be running under a different user, same for either of them and FTP/SFTP. If you are unsure, ask your host about it.
Kindly note that we are here because you asked me for technical support on the basis that I know more about the software and how servers work than you do. If you are here to be passive aggressive, ignore me, do random things which make it impossible to know the state of your site between each reply and make arbitrary assumptions in stark contrast with objective reality I can not help you.
Nicholas K. Dionysopoulos
Lead Developer and Director
🇬🇷Greek: native 🇬🇧English: excellent 🇫🇷French: basic • 🕐 My time zone is Europe / Athens
Please keep in mind my timezone and cultural differences when reading my replies. Thank you!