Ok just to clarify for anyone that reads my posts.
Even though my i3 said it failed to update tire size it was in fact successful. I have since adjusted tire size multiple times to get my speedometer accurate against a gps speedometer.
Aside from the failure message on the tuner, completely ...

In the quick tune section of my up to date i3 it says it did not accept size change from 285-70 r17
To 37-12.50 r17 but I’m realizing now even though it says it’s not accepted it may in fact be accepted because my speedometer is only off by 2mph.

Oh. By the way, 2013 ram 2500 powerwagon…

One of the main reasons I purchased the intune was to modify tire size.
Now that I’v added 37’s to my truck, my intune won’t accept the size change.
Is there something I can do? Is this a known issue?