Advanced call forwarding not available

Same problem posted many times, but I never see the resolution. I want to set up nomorobo on my voice line. To do that I have to enter a nomorobo number to my advanced call forwarding list. But the advanced call forwaring tab says "Sorry but something went wrong" and then I go into an endless search for how to fix that, always unsuccessful. I see some experts ask for detailed account information, after which they may be able to solve the problem. Is that what I need to do, and how do I do it? Thanks in advance