There’s no Firerwire card with the AXR4.
Sam refers to an AXR4 and a UA Apollo. ARX4 connectivity issue as main interface as cannot get the computer to see it. Also issues connecting it to an Apollo via ADAT as some setup on the AXR4 is required in order for this to work as required.
What’s your specific issue?
Also, its much easier to get help when you have a sig applied to your profile, detailing your comp spec, OS inc version number and connected hardware and DAW, inc version number. Issues with PC’s and Thunderbolt mean its a good idea to inc motherboard info and any 3rd party TB cards used.