Gmail's confirmation verification never arrives

Question

I've seen questions about this dating back to 2009 - but not a single answer. When I add a new email to my Gmail account, I can send and receive from/to that email through my Gmail account no problem.

But, I can't add it as a "sent from" until I get the verification code from Google.

The only thing is, no matter how many times I've sent and resent this confirmation email, it does not arrive.

Yes, I checked my spam, trash, and all filters.

No, it is not hosted by someone else. It is a forward.

Yes, I have other addresses from the same place that work just fine.

Yes, I can send emails to (and receive them from) this account, through my Gmail account, no problem.

The issue is with Gmail's verification.

Please, from the experiences I've seen here, I know Google will not answer. Does anyone have a way to glean the code that does not involve this non-existent email?

Answer 1

Try to

1. have the email address first forward to a non-Gmail provider (like protonmail)
2. send and use the Gmail verification code/link received at this provider
3. change forwarding to Gmail account
4. test if Gmail can receive

Ridiculous, I know.

Answer 2

Finally have the answer after having the same problem myself for months. The Gmail inbox is divided into primary and social. The Facebook message will be in the social division. Hope that works.