I'm having the same issue.  When I upgraded to QB Advanced a couple months ago, I all of a sudden needed to to re-verify my Venmo account with every update.  Annoying, but doable.  Starting a couple days ago, I'm unable to connect to venmo at all.   I've double checked my venmo.  I can log in fine there.   I tried to update venmo in an incognito window as we recommended in this thread but that didn't help.

The error code I get is 103.

Given the number of people experiencing this issue with the recommended fixes not working, let's do better Quickbooks!  We rely on you for up to date financial information.   I can't just not have a key account not included.