A bank on Intuit's list is not automatically a Web Connect bank
QuickBooks Desktop downloads its own directory of financial institutions, and that directory describes mechanics rather than brands. At the last count it flags 5,800 entries for Web Connect, the route a .qbo file travels, while 2,588 entries are Direct Connect only. That is a live link your bank switches on for the account, sometimes as a paid service. Same directory, two different worlds. When somebody says the bank is supported and the import still refuses the file, this is often what was going on.