Regex not working in Okta


#1

Hi,
I am trying to define a Regex pattern for my Identity Provider to only allow certain users from a certain domain.
After a bit of trial and error, I found this input that I have been using until now: .*@mydomain.com$
However, it seems I need 2 more domains (mydomain2.com and mydomain3.com). I dont really know regex, but after some research and guessing, I was able to find a string that I got working in https://regex101.com/
New input: (?i)(?:.*@mydomain.com$|@mydomain2.com$|@mydomain3.com$)

I added the (?i) to ensure that its case insensitive.
This new Regex doesnt work. My Okta keeps rejecting the user I use for testing.

What am I doing wrong?