It could not write the image... dem.ElevationError while preprocessing of image using snappy (python interface of SNAP)

the code was running fine a few weeks ago but suddenly it is throwing a dem elevation error infininte times whenever i am running the script. I think it is not able to download the dem or something. I dont know what is actually happening here. can anyone please help me. Its’ urgent.

here is the screenshot for my error console. What should i do to avoid the error and output the .tif image.