Bulk mail from local mail server failing to deliver after switching to Exchange Online
by mfoley from LinuxQuestions.org on (#5B21G)
Our office switched to Exchange Online a few months ago. But some email is still sent locally from our webserver and production system. These include "group email" which can be sent to 1000-ish people for general information, and "check stubs" send from the payment application and can also be around 1000-ish emails.
Most recipients get the messages but some, predominately to roadrunning.com, rr.com and other domains serviced by RoadRunner such as charter.net, centurylink.net and embarqmail.com, get nothing at all. The messages doesn't go to their spam/junk folders and the local maillog (Sendmail) has a status of "stat=Service unavailable", which I believe indicates rejection on the recipient end.
I'm looking for advice on how to get these recipient mail servers to accept these messages.
Our MX record is mydom-org.mail.protection.outlook.com. Could I add a 2nd MX and/or PTR record for our webserver host?
Could I somehow use Exchange as a Smart Host?
Other ideas?
Most recipients get the messages but some, predominately to roadrunning.com, rr.com and other domains serviced by RoadRunner such as charter.net, centurylink.net and embarqmail.com, get nothing at all. The messages doesn't go to their spam/junk folders and the local maillog (Sendmail) has a status of "stat=Service unavailable", which I believe indicates rejection on the recipient end.
I'm looking for advice on how to get these recipient mail servers to accept these messages.
Our MX record is mydom-org.mail.protection.outlook.com. Could I add a 2nd MX and/or PTR record for our webserver host?
Could I somehow use Exchange as a Smart Host?
Other ideas?