"This email address is not valid for use as an Apple ID"
If you use work e-mail and you just got the new e-mail account from work, it probably uses a work domain.

It extracts the MX records from the email address and connect to mail server (over SMTP and also simulates sending a message) to make sure the mailbox really exist for that user/address. Some mail servers do not co-operate in the process or have a delay, in such cases, the result of this email verification tool may not be as accurate as expected.

This technic of E-mail validation through the sending of an E-mail interrupted before the end is a technic used by criminals to perform stealth E-mail verification. This is the reason most serious companies will block these interrupted SMTP handshake. This is a bad method to check an E-mail.

Often with not recognized or newly registered domains Apple takes a few days and then it will magically accepts the e-mail.

You can see here https://verifalia.com/validate-email what a e-mail validator will check. And the results.

If it doesn't work after serveral days, you should contact Apple Support.