Emails from some servers are not recieved

Emails from some servers are not recieved

I am setting up aliases as necessary for my SSL certificated which needs to verify a specific email address. The email address test fine from gmail. zoho, yahoo but the SLL provider sends an email to it but it never is in my email? I check Spam, Deleted and all folders.  They insist they have sent it. The email is admin@nwchairs.com, an alias in my gaanes@zoho.com address. Yes I also check the gaanes@zoho box as it is the catchall address.

The sender is  orderprocessing@rapidssl.com   and yes I have whitelisted the address.

A mystery since I can receive emails to that address when I test from another server.

Greg Aanes
2109 Queen Street
Bellingha WA USA