Hi, am having the same issue "failed to open connection to server using gateway" I tried your advice to Marianne, I tried to open through my MacBook as well as my HP laptop, using safari/window ten explore..please help, I am already behind with invoicing and banking reconciliation.
I have had this issue with a few of my client logins. Check Control Panel first to make sure no one is logged in. Then log in if message comes up, log in and out . You may have to do a couple of times, but I evenutally have gotten in each time. Hope this helps