When I tap into a spiral duct I occasionally get the error message on the attached screenshot. I can keep trying and then it will work. Or it will work okay then give me the error on the next tap beside it. This is the Revit 2022 imperial database that I've modified and maybe that's the problem. I don't recall having this issue on earlier versions. I also created a new drawing and it's having the same problem, which I've attached too.
I have ran some test on the Autodesk out of the box database ductwork and was able to replicate the same error.
Try the following workaround. Turn off all SNAPS except the Points (SX). It will connect easily without trying to find a specific snap point like MID, NEAR, INT, etc. I notice in my test that when placing a tap on round (spiral) the SNAPS would pull to the MID point and that's when I get the error.
I hope this helps. Let me know if you get the same result.
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