Cloud access not working for users after OS 5

After upgrading to OS 5 (latest firmware 5.12.108) I as the device owner am able to log into the cloud access…however none of my other users can log into cloud access. They receive the email with the link to create their account, do so and then when they log in they receive a message saying “Request rejected - the device owner rejected your request”. I have not seen any request nor would I have rejected it.

Things I have tried:
Restarted the EX2 Ultra several times
Turned the cloud service on/off
Logged in/out of cloud service (does it seriously re-index all the data every time I log out?!)
Created a new user from scratch - same error

Any help would be greatly appreciated!