SiteCollectionAdmins - SetPnPTenantSite

[ttd-kevinclement]

Hoping someone can help answer this. Why are some users not valid as site collection admins when using the following commands:

• Add-PnPSiteCollectionAdmin -Owners "user"
• Set-PnPTenantSite -Owners "user"
  Errors for the above commands look like such

It seems this behavior is also happening in the OneDrive web gui. What is the criteria for a valid site collection admin?

[AndersRask]

Works in my testing, so try and look up the users in Entra ID and see if the account is enabled.
Also policies could restrict adding external users.