Hello, I was reading this guide https://docs.suitecrm.com/admin/installation-guide/downloading--installing/ regarding setting permissions as I managed to install the system, but, it would not log in. I was concerned that setting the permissions might mess up things that are running on my server or lose me control of the directory. I didn't think they would be compatible with ISPConfig so I was looking for your advice please so that I make sure I do things properly. Thanks
The permissions as described in the tutorial are wrong for an ISPConfig system indeed. Change the user and group of all files to the web user of that site and the client group of that site instead of www-data. The chmod 755 is ok and can be used like this.