Omnirig won't connect

I'm using an ic-707 and a signalink, so have to use omnirig, however here is the error:

19/02/2023 01:23:59 - OmniRig: Unable to connect OmniRig.

19/02/2023 01:24:08 - Closing com port

19/02/2023 01:27:49 - Debug mode disabled

19/02/2023 01:27:49 - FREQ Schedule off

19/02/2023 01:27:50 - OmniRig: Connecting to OmniRig...

19/02/2023 01:27:50 - Error: Starting OmniRig: Value cannot be null.

Parameter name: type

at System.Activator.CreateInstance(Type type, Boolean nonPublic)

at System.Activator.CreateInstance(Type type)

at VarAC.VarAC.StartOmniRig()

Thank you