We have two Smartermail server. Both are hosted in different datacenters and are different Smartermail versions.Starting about a week or 2 ago, emails coming from Office365 hosted accounts get delayed when sending to any domain on either of our servers. We have done a message trace on an Office365 account and it reports pending because the server blocked the connection or socket error. (0% of the time the message will go through after future retries by the Exchange server but it could be hours or days. About 10% fail do to time out. We have tickets open with Microsoft but they have not been very responsive. We have all the listed IPs from Microsoft added to our whitelist and that doesn't make a difference. Is anyone else having an issue or have any idea? We have been struggling for days and have hundreds of upset clients thinking its us.

 

Any help would be appreciated!

 

Note: We have no issues receiving email from any other service provider (i.e. Self hosted, gmail, yahoo, etc).