I've just installed OctoberCMS and I wanna use the CMS interface to modify some files but whenever I modify I file I get an error? which is actually getting the whole HTML of the file displayed back in a modal frame. I checked the file permissions and it's 0644 so it should be fine, doesn't it?

@ffuentes Is the owner of the file the same user that your web server runs as? ie. if your webserver uses www-data as the user, the files need to be owned by www-data as well.

I've checked it and the hosting uses my username for everything. www-data is not used at all.

I used the Chrome developer extension to check what happened at the moment of saving modifications and I get a 403 HTTP error and the response is odd, I get the whole page back as response and no explanation of the error.

I talked to my hosting provider (namecheap) and yet they couldn't find the problem. The fact that october doesn't give any explicit errors doesn't help.