I am answering my post, b/c I was able to figure out how to resolve the issue. I disconnected Tiller<->capitalone link/connection, both on Tiller side and on the CapitalOne side. As well (and I dont know if this helped at all) I disconnected my old mint link/connection from my CapitalOne and quicken. I basically cleaned up any old connections I had.
I then came back to Tiller and reconnected and both accounts finally showed up.