There is a server log feature in UBB but it is only for mysql and it would need to be enabled.
For mod_security it is a php module..
So it would be a error log for php.
You may not have access to it depending on your hosting plan.
But I would look in cpanel or whm. whichever is available.
Look for something about logs and php.
Or try file manager in cpanel and see if you have a similar folder above the root if you are able.
Or you may need to just call the host to check.
