I've been having the same problem for three weeks now, ever since the credit union rolled out its new mobile app. Due to whatever changes were made in association with the software switch, now Mint can't update my main checking & savings accounts. (The new USSFCU mobile app is fantastic though.)
I contacted Mint about it today. They said that USSFCU is using a new enrollment process that is blocking third party aggregators (like Mint) and that their tech team is looking into the problem. Fingers crossed that the issue will be fixed soon.
