EXTREMELY FRUSTRATING...One thing I have noticed in all this troubleshooting is when you finish a return and are ready to transmit to Docusign, first close ProSeries and then open again and before you do anything else go to EF Homebase and attempt the Request.  This has worked for me a couple of times...I have been saving three or four returns before attempting just to limit my frustration!  It seems if you get one to go you can do more right after...