Background: I have checking and savings account at my credit union. My wife does also. Same credit union.
All four are associated with accounts in our Quicken. Prior to last summer, the OneStep Update worked just fine. Wasn't there some kind of major change in July or so? About that time I had issues with updates.
I made the mistake (apparently) of disabling Express WebConnect for my accounts and then trying to set it up again. Quicken failed to make connection with the credit union. I've been trying again every few weeks with no success. And, yes, I always verify that I'm using the right credentials.
Meanwhile, after an initial wait of several weeks, I can update my wife's accounts, no problem. So obviously Quicken can connect to the credit union for that purpose.
I did chat (more than once) with Quicken support, one time for more than an hour doing some kind of remedy. In the end they told me the problem wasn't resolved and I should wait. It's now been more than 4 months of waiting …