I was able to successfully couple the Transient Structural and Fluent together. I think I was able to resolve the issue after changing the dynamic meshing in Fluent.
My project simulates airflow within a deforming cylindrical tube. My model was a 1/2 model with symmetry assigned (since the number of elements/nodes were limited by ANSYS student). Instead of selecting the entire fluid as deforming, I selected each plane (other than the system coupling wall) and assigned them with deforming. After this change, the system coupled successfully without any SC service crashes and other errors.
However, I had to resolve another issue (as posted here) which may or may not relate to this issue of this discussion. Anyhow, I hope what I experienced helps you in some way.