Be aware that moneydance has one or more bugs in the area of saving and using online bank acct passwords. I have simply not had the time to fully untangle exactly how this bug behaves. It is a most maddening bug. make sure you have the right userID and password for each account, and in the passwords entry in the menu bar file pulldown uncheck the option to save your passwords. Enter them each time you synchronize your data with the bank until things are working. Only at this point can you recheck the save passwords option.
Each time you change the save passwords settings restart the program for the change to take affect. Good luck trying to get help out of the Infinite Kind support staff, as they appear to be badly undermanned for the workload that they are facing.