Overjoyed today to find that this issue is resolved which I reported here.
I'm now able to connect to my PennyMac account but am unable to link to my existing Quicken account which I've been updating manually since May. It seems the only option I have is to create a new Quicken account.
In my existing Quicken account there is no Online Services tab in the Account Details dialog. During the Add Account process there is no option to Link to an existing account (see pic).
Is this the expected behavior?