Thank you for your answer @lveci. I successfully performed the TF on this image. I think the algorithm now support the poles. I was able to complete the process with my own DEM in UTM (TanDEM-X resampled to 6m resolution) and also in Polar projection (REMA with 8m resolution).
The solution was your reply in another thread advising to multilook the images to the same resolution as your DEM:
It will be nice with SNAP could incorporate in TF and TC GUI the option to auto download DEM specifically to the poles, like REMA.
Thank you again for your attention.