Water leak interior 2006 extended cab with sunroof

[Buddy67Lincoln]

Well it poured and noticed my passenger side seat was wet,then the roof panel, all the way down the door post. 2006 sierra extended cab with sunroof. Might it be a clogged sunroof drain? The cap that covers the B Post top latch bar was full of water. It wet half way between the edge of headliner and the sunroof. Pulled the grab handles, A post cover, and the door gasket on top. Didn't see any Drip from the drain I could see. Any usual areas to look at if this is a common issue??? Thank you