Welcome Email not receiving from Tealium

[Atul1]

Hi Team,

I have added a user in Tealium IQ with a correct email address. 

But he is not receiving any welcome email or any support email from Tealium in outlook. Because of which he is not able to login into the Tealium.
We have checked the outlook configuration and setting and no blocking rules are applied for that.

What might be the reasons to the only specific user is not getting a welcome email from Tealium? 
How we can create a Tealium account for the same user? 

Note: When we add the other users from the same account, they are getting the welcome email from support Tealium.