Hello @craig.
Thank you for reaching out on the community and telling us about your issue. I do apologize for the late response. You've already tried a bit here as well. Like you stated you haven't changed any account info either.Have you tried to deactivate and reactivate the accounts? If not I would recommend trying that to see if we're able to get them all back and connected together again. The article here has the steps provided a bit down the page.
Please let us know if this helps resolve the issue for you.
Thanks,
Quicken Francisco