Hello there,
I tried looking this up, but was unsuccessful as I didn't really know how to phrase the question. Here are the details:
- My email account has been switched from first.last@domain.com to first@domain.com
- first.last@domain.com is now an alias to first@domain.com
- This is now the real account
- When I try to change my email Manage Your Account, I get an email to first.last@domain.com saying that I should check first@domain.com, however I never get the email at first@domain.com
- I wonder if the fact that the email is an alias of itself is causing issues with the mail even being sent
I'm a site admin for our cloud instance, so I imagine I should be able to make whatever change necessary from your impending solutions 
Thanks in advance!