I am using an app called SetList on my IPad Pro. Its used for uploading songs charts. It uses Dropbox to upload from. Recently when I try to connect to Dropbox to upload a file, the Dropbox login page opens. I can enter my username. Its says welcome back and after I enter my password. it just spins the status square. I am running 13.1.3 on the Ipad. The Setlist app has not been updated in years. Any suggestions would be greatly appreciated.