I have a client that is a Law Firm. They are trying to send emails to a company that uses Outlook.com as the host for their emails. Whenever my client sends an email to the company, the messages sit in the outgoing queue of their server with the error 4.7.7.
When tested from my own exchange server emails are delivered to their server. (delivery receipt received)
When I check the hosted domain via MXToolbox, it reports all is ok
My question.
Does a customer who has email hosted on Outllook.com have any ability to block a sender (either in a spam filter or junk mail filter) that would cause this to happen and generate the 4.7.7 error.
I am wondering of the company is actually doing something to block my Clients email domain from being accepted in some way.