Trying to send Activation - email not being sent

We are transferring a Creative Cloud license from one use to another.

I have the new person's name and email entered and it is showing on screen - with a status of "Invitiation Sent"

I have clicked the "Click to Resend" link multiple times, but no email is received.

We've double- triple-checked the email address it is correct.

Please advise how we can get the user license account activated.