outgoing mail returned undeliverable

[dalew123]

Our server was used as a mass e-mailing site lte last week, since then exchange has been updated to close this hole.
However, since then staff can only send e-mails with our own domain, or our ISP's domain, any/all other e-mails to different domains are returned as undeliverable?

Any thoughts out there?

Thanks

 

[Grenage]

Mass email as in spam ?

If so it's possible you may have been blacklisted a guess, although that wouldn't be to every single address excep your own.

 

[SFTechie]

As Grenage stated, you might have been blacklisted. Check with your ISP to verify. We had some issues with one of our clients who was placed in a one of the many blacklists out there.
Good luck!

 

[Spirit]

I'd say that the update may have removed your routing configurations for the way in which your mail is sent check you routings.