The last version of MD 2015 was MD 2015.8 (1372)
I would start by updating to that version. Provided that you purchased Moneydance through the Moneydance website (as opposed to the Apple Store or elsewhere) then you can d/l the update here. http://infinitekind.com/download_2015
My wife had a similar issue with Chase but could not even log on to their website.
After we changed her password, she could log on to their website and once we made the changes in Moneydance, she was able to connect again. We're using MD 2017.10 (1706)
There was also another user on the forums with the exact same problem as yours. He changed his password and was then able to connect to Chase. I don't remember what version of Moneydance he was using.
If updating Moneydance doesn't resolve the issue, you may want to try changing your password at Chase. If all else fails, you may need to update to MD 2017.
Check here to see if you can update for free by plunking your license key into the 'Upgrading' field:
The same provisions apply as above. http://infinitekind.com/purchase