I am having the same issue in the last 10 days. There is no error message, and the total AMEX bank balance  is updating daily per normal, but there are no new transactions coming over to QB since 1/21/19.

Spent 2 hours with QB chat support yesterday, and after all that finally got the answer that this is an open issue they're investigating. Not clear why it took 2 hours to get that answer.

Mint used to have these issues constantly, and I dealt with them because it was a free tool -- but we pay good money for QBO, and this sort of business interruption is totally unacceptable. (And why can't they message errors or known issues within the tool, so we don't ALL have to contact their help desk? So dumb.)

QB team -- please help and tell me when this is going to be fixed!!