I have a vBulletin forum. Once I want to subscribe on a thread (post), it's giving me an error saying that I've been logged. I have contacted the vBulletin forum manager and they said it is a webhosting issue. So, I am now here to get help for that.
Troubleshooting this would require solid knowledge of how vBulletin works, and it's something that they should be able to do well.
Absent further guidance from them, the first thing that you should do is look to see if you installed it in a subfolder with a parent that contains an .htaccess file. For instance, if you installed it inside of a Drupal installation, that would certainly break it -- putting anything inside Drupal does not work. If so, you should move the vBulletin installation elsewhere.
On our end, in terms of the global configuration, we use the standard Apache stuff. I know that many customers have used vBulletin successfully.
This is something that you can see through your FTP/SFTP client as long as you have it configured to show all files (by default, many hide files starting with a ".").
