Greetings,
Dumb question. Are you performing all of your tests with the HD IO's attached and powered on to the HDX card? Correct that prior to Pro Tools version 12.6 you would not need a DigiLink license to use that peripheral and engine.
https://avid.secure.force.com/pkb/ar...-O-license-for
Yes - the error should indicate - specifically that it cannot locate a DigiLink license if indeed that is the issue.
Jeff