Hi,
I'm trying to add two different users in the PowerApps Admin center via the Security tab > Step 1: Add user [Preview]. Every time I try typing their email and clicking 'Add user' it gets stuck on the 'Working on it...' blue notification and never goes any further. I've been able to add them successfully (with the system administrator role assigned as well) to a Sandbox environment, but am not able to add them to two different Production environments.
Both users have a 'PowerApps for Office 365' licence. I've also tried adding a user with a 'PowerApps for Dynamics 365' licence (just to compare) and I encountered the same issue.
Not sure if it's relevant but both environments used to have a security group linked to them, but I couldn't get that setup working/syncing with AD and actually enabling access correctly. It sounds like (from https://powerusers.microsoft.com/t5/Power-Apps-Governance-and/Cannot-add-user-to-environment/m-p/455131#M1943) that it's not possible to remove security groups but I just deleted both instead from the Dynamics admin center.
I'm not sure what else to try, all help appreciated. Thanks!