gmailgoogle-apps-email
When I attempt to address my email message by selecting a group and hit SEND I get the error message:
The address "seeminglygoodemail@example.com" in the "Bcc" field was not recognized. Please make sure that all addresses are properly formed.
If I select this particular email by itself it works. I've verified that the email is well formed.
No Gmail will make a duplicate contact out of it, which you will have to merge 'manually'.
Luckily this is a very easy process, though it may take some time if you don't keep up with it.
Gmail even helps you find duplicates if their name doesn't change much. Else you just have to select them both and click [Merge]
(source: blogspot.com)
(source: blogspot.com)
I was't receiving the email because I had a previously-created-forgotten-about-and-not-in-production Google Apps account for example.com. As a result Gmail was delivering the verification email to the Google mail servers since from Google's point of view that domain's email is hosted by them rather than to my external example.com mailer.
Best Answer
It seems that the email address had a bad character that is not visible. Perhaps a Unicode 2-byte character that Gmail is displaying properly but storing as two bytes and tripping up its own parser.
The solution is to simply re-enter manually the email address.