Imposing a rotating boundary

Hi,

I am trying to build a laminar flow model with a rotating boundary to shear the flowing liquid. Unfortunately, when I impose the equation of this rotating boundary, the rotation equation appear correct when I check them manually; but the software does not interpret them correctly and they appear yellow. Please advise on what may be the issue at hand. The model is attached below if you may be helpful enough to assess the model itself and see if you may notice the cause of this error.

I appreciate your help!

Sincerely,
Michael