Remote Server returned '550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup'

Question

I have an exchange server 2016 and I've created a user, say [email protected]

I followed the steps as told in this video: https://www.youtube.com/watch?v=GN2mZ6qOWf8

I'm trying to send a mail from [email protected] in the exchange server to any outlook account in the outside world, for example, [email protected]

But I'm unable to send a mail from testuser1 and I'm receiving this error on the exchange server Remote Server returned '550 5.1.10 RESOLVER.ADR.RecipientNotFound; Recipient not found by SMTP address lookup'

Is it even possible to do so because both the domains are completely different or am I missing something here?

Answer 1

The recipient email account is not found or doesnot exist. Even sending an email from Gmail gives "Address not found Your message wasn't delivered to [email protected] because the domain outlookdomain.com couldn't be found. Check for typos or unnecessary spaces and try again".

Answer 2

From [this article][1]:

Although the Recipient Filter agent is available on Mailbox servers, you shouldn't configure it. When recipient filtering on a Mailbox server detects one invalid or blocked recipient in a message that contains other valid recipients, the message is rejected. If you install the antispam agents on a Mailbox server, the Recipient Filter agent is enabled by default. However, it isn't configured to block any recipients. For more information, see Enable antispam functionality on Mailbox servers.