I am using Collector with Portal for ArcGIS with portal-tier authentication. I have several users who cannot see data when a web map is opened. The map is shown in the available maps but no layers are displayed. If I give the user a different iPad and have them login they are able to open the map and all data is displayed. Definitely related to something being stored on the iPad. I can have two users logout of Collector, trade devices, login, and layers are shown. However, once it happens to a user on a device no amount of rebooting, logging out, or closing and reopening Collector will fix the issue.
Update... uninstalled/re-installed Collector and the user is still not able to see the data. Collector is burying something deep in iOS that is preventing the user from viewing any of the layers in the web map.
Bryson,
Have you tried changing the user's password? I saw this issue occur after an iOS update earlier this year and changing the password resolved the issue.
BUG-000111468: After upgrading to iOS 11.2.5, the Collector for Arc..
Removing the user from Portal and then adding back has fixed the issue. Thanks for the help Dan!