I have had a similar issue. things worked fine then all of a sudden had to re-enter our credentials.  Received a 103 error.  I confirmed my account information and contacted support.  Went through all the required suggestions and still nothing.  I reported support and this is my case number 1576311207.  this was over a week ago.  I contacted Venmo and my account credentials are correct.  This is a QBO issue!  Any advice?