So, I could not connect to ML from either the TT Desktop version or the TT Online version (last year or this year). I'd called TT/ML support several times and got all the same general troubleshooting answers. I even had our ML financial advisor working on it from their end.
2 days ago, our FA reached out and they were able to confirm that this was an ML issue that was created when they did some back end changes some time ago. The ML tech ended up creating me a whole new login from the back end giving it the permissions needed to connect TT. I tried it yesterday on the Desktop version and I now have all my ML tax info imported. I'd call ML or your FA back and have them specifically get with back end tech support (not account support). Let them know this is a confirmed issue on the ML side.
Good luck!
