Update: 10/11/18 - I was able to login today. Not sure what happened, but it is working for me now.
I see that several people have commented they cannot login in via the WU mobile app. I have the same issue. I purchased a new iPhone XS Max on Saturday and have not been able to get logged in. It keeps telling me; "Sorry, there was a problem connecting". I have deleted and re-installed the app twice, performed the "Forgot Password" process, but nothing seems to work. I'm logged in on my iPad and my PCs, just not the new phone.
I have submitted a ticket to WU, waiting to hear back. If anyone has a tip on getting past this issue please let me know.