Hi
We are trying to send emails to few customers who are using Message Labs as their Antispam solution. About a week ago the emails sent by us to those customers started disappearing but it worked fine for years. We use Office 365 in the cloud and I can see on the logs the emails being passed onto the "cluster..." mx record server of those customers, howver, our contacts on our customers' side report that they never got an email. I have spoken to Office 365 and they confirmed that our settings have not changed. I ahve checked our domain for reputation and Office 365 support confirmed that they are not blaclisted either. I do not know whether we received any NDR when it started going wrong but we definitely do not receive any NDRs now. It is weird that 4 of our customers using Message Labs are affected so I am wondering whteher there was an update on Symantec side. Unfortunately, Symantec doesn't wan to talk to us because we need to contact IT departments of our customers but these customers are banks and we cannot get through to their IT. We have been dealing with these banks for long time and now they and us are losing business because of that issue. One thing we noted that sometimes emails do go through if we send them as plain text but not always as sometimes those are still blocked or end up in end users junk folder.
I would appreciate if anybody could shed any light on the issue or help to get the issue sorted.
Thank you
Kind Regards,
Tom
