Some things to check:
* Line / Inst switch is set to Inst.
* Volume on the guitar is set to maximum
* Disconnect whatever else is connected to the interface while recording, except headphones.
Regarding the last point, you might have a ground loop with computer and powered monitors (or your amp) through the USB ground and the interface. Using balanced outputs of the interface to feed the monitors might help.
Otoh, without having heard it, some light hum cannot be prevented and with high gain settings it can become problematic indeed.