Fuel leak

If you have fuel pouring out of the canister and not the line then you will need to replace the canister and that should come with new vents in the top. Basically you have a vent that is plugged and as you are filling it will create a suction in the canister and pull fuel in from the tank. This will cause it to overflow.

The other possible cause is that the purge solenoid is stuck open and if you are filling the tank with the engine running and the purge is open, it will pull fuel into the canister and eventually it will overflow.

Please take a look at the info below on this and I would start with replacing at least the canister if not the solenoid as well.

Please let us know what questions you have and we can go from there.

Thanks