Why am I getting an error when receiving mail from Outlook.com?
I have recently started noticing the following issue whenever my smtp server receives mail from outlook.com. Right after delivery finishes, I receive the following error:
2020-06-16 02:39:54 SSL_write: (from mail.outbound.protection.outlook.com (outbound.protection.outlook.com) syscall: Connection reset by peer 2020-06-16 02:39:54 SSL_write error 5
From my research, it seems that some Outlook servers are blacklisted on spam lists by Exim, which results in the handshaking failing and resets the connection. I believe this is what is happening to you here.
I was able to find some steps to take that may resolve this issue:
I recommended adding
/etc/virtual/whitelist_hosts_ip, as well as adding the below to
outlook.com outbound.protection.outlook.com mail.protection.outlook.com