'Authorization'?

[Penumbra]

I wanted to leave Tuluk, but the gates wouldn't open. The guard said 'You aren't authorized'... what's all this about?

[ashyom]

This is fairly common knowledge so I'll answer to an extent:  only a templar or soldiers of certain rank can open the gates after they've been closed.  They have a good reason to close the gates.  If you wait at the gates awhile, you might be able to figure out why.  Also, if one gate in Tuluk is closed, that doesn't necessarily mean all the other gates are also.  You can try finding a different exit.

[Halaster]

However, all the city-gates get shut at night and get re-opened in the morning.  So if you're trying to leave/enter the city at night, that's likely why.

[Savak]

Actually Tuluk doesn't have a regular nighttime gate curfew, although the gates may be closed at ANY time given the proper circumstances/local dangers/templarate whims.

Feel free to try to bribe a soldier or templar to open the gates for you, though if you can't find a PC to do so you may need to "wish all <message>" about it.

-Savak