Fuel solenoid leaking M11

[Hemiterry]

I have an M11 Plus in a 96 international 9200 tandem dump truck. A few weeks ago I noticed fuel leaking from the fuel shutoff solenoid where it bolted to the pump. I ordered a new solenoid which came with new ring gaskets. After replacing everything it still is leaking. I’ve taken it on and off 4 times now and still can’t stop the leaking. I’m making sure all the surfaces are clean and using a thin layer of o-ring lube on the gaskets. Any ideas on why I can’t get this leak stopped?
Thanks