I have a 2011 Chevy tahoe I have taken to dealership already for the gas tank not filling but shutting off.A new canister was installed did not help

[Bill Barnes]

They need to test the evap solenoid under the hood for being stuck closed. Common cause of this issue. I'm surprised they didn't start there first. Also ask them if all the charcoal was in the canister they replaced. If not, then the lines need to be blown out and could be limiting flow to the evap solenoid on the intake.

I agree. I just had a similar issue on my 2005 Yukon XL. It was a a bad evap solenoid. My local shop fixed it with an OEM part for a very reasonable price.