XF 1.5 Forbidden 403 error when editing templates

[neokyle21]

When trying to edit and save changes to certain templates such as navigation and messages I receive the following popup error and am unable to make any changes.

The following error occurred:

Forbidden

You don't have permission to access /pvp/pn/admin.php on this server.

After some research the error seems to be typically caused by mod security so I contacted my host. They told me mod security wasn't interfering and gave me this error from our logs saying that the problem seems to be on xenforos side.

POST /pvp/pn/admin.php?templates/save-multiple.json HTTP/1.1" 403 225 "http://mysite.net/pvp/pn/admin.php?templates/navigation.1015/edit&style_id=22" "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36

Some of the templates I'm trying to edit are ones I've successfully edited in the past. I recently upgraded my xenforo from 1.2 to 1.5.7, as well as my style and add ons.

 

[Paul B]

This is not a bug so I have moved the thread.

It is typically due to mod_security and your host needs to whitelist the offending rule or disable it.

 

[neokyle21]

This is not a bug so I have moved the thread.

It is typically due to mod_security and your host needs to whitelist the offending rule or disable it.

Yes I do believe it might be mod security as well but the support rep I spoke to said the above error was all that was within our logs and that it wasn't related to mod security. I asked if they would turn off mod security and they said that they don't disable it. How can I find out what the offending rule is to have it whitelisted? Maybe I just spoke with someone who doesn't know what they're talking about?