First we'll try deactivating all of the accounts for the affected FI. You can do so by following the article listed down below.
https://www.quicken.com/support/deactivate-online-banking-services-quicken-accountOnce all the accounts are deactivated go ahead and follow the article here on reconnecting the accounts.https://help.quicken.com/pages/viewpage.action?pageId=3216277
Once you've had the chance to attempt these steps let us know how it goes. Thanks,Quicken Francisco