How long does Skype for Business take to update sign-in? Can't login after AD/O365 user update.

[Jgq85]

Added and verified a second domain in O365. We have an on-prem AD with same suffix of said domain. No skype-on prem -- we just sync via Azure AD Connect to O365.
Updated a user's UPN, mail attribute and primary SMTP to the user.name@newdomain.com address. Syncs to O365 just fine. Outlook, OneDrive, etc. all update fine.
Skype For Business however, doesn't like it. Even 24 hours later. Apparently we can sign in with @newdomain.com in the "sign-in address" field, but have to put the @olddomain.com in the "user name" field in order to sign-in.
It's been about 30 hours since the change I've no idea why it would take this long if it is a syncing issue in O365.

It's not a Skype for Business client issue. Tried on another computer and on mobile devices, it just won't sign in straight up with the new sign-in address. 

[#2 · Accepted solution]

@Jgq85 

Fixed it.

Apparently over in Okta, our service used for SAML/MFA, the "username" for the Microsoft Office 365 app was still the old e-mail as it doesn't auto-update. Skype for Business was apparently the only application that was affected by this yet nothing in the logs indicated it. I just happen to go check and see it, then change the username there to the new domain, and bam I'm in.