My guess through experience is that your tank vent is blocked.
If the volume of air that is in the tank cannot be displaced through the tank vent when you add fuel to the tank the air has only one place to go, back up the fill tube. When this happens it causes the pump it to trigger the shut off. Find the vent line where it exits the boat, it should have an access port, disconnect it, remove the exterior vent and inspect it I bet you a critter made a condo out of it or it’s blocked with salt deposits. If not next check the vent line to tank. The other possibility, although remote, is that there is an obstruction in your fill line. Did you do any work around the fuel fill or did you make someone mad enough to stick something down the fill tube?