Trouble fueling

I am having trouble fueling my car with gas. Anytime, I try to put gas in the tank, the nozzle stops after seconds of dispensing fuel. Regardless of how fast or slow the fuel is dispensed. Does the evaporative vent system come into play during this process? Or could the problem be an obstruction in the filler hose? Or possibly an anti-spill valve in the tank? Thank you, we have done a little research online, and these are the questions remaining.

Evap problem. Either a faulty evap vent valve or a faulty filler pipe assembly.

Those are my first guesses.

The attached document may help. It’s a representation of a typical evaporative emissions system. When you’re filling your tank, the vapors are pushed past the diaphragmmatic valve, through the charcoal filter, and to the vent by the fill tube. Possible problems in your case are the valve at the top of the tank (unlikely), the diaphragmmatic valve, and a saturated or otherwise clogged charcoal bed. If you “top off” your tank, this can in some vehicles cause saturation of the charcoal, so it’d be a good idea to discontinue the practice.

http://tijil.org/Scion_Docs/Scion_06_misc_docs/2007sciontc_ncf%20Folder/2azfeemi.pdf