A client continues to receive a "Failed all attempts to connect to recipients mail server" message trying to send mail via my SmarterMail server (v12) to an address whose organization has an Office 365 cloud mail server.
Only info back says cannot connect (with code 221). No indication of rejection, etc.I talked with the people with the 365 server, and apparently they do not have access to any logs (or don't know how to get them). Seems without their logs I cannot tell whether the connection problem is theirs or mine. Below is more of the SM logs for one of these attempts (the summary after 8 hours of attempts.)
Any ideas of where the problem might lie? Any settings I should consider on my SM; or they should check on their server?
Appreciate any help or direction.
--- SM log summary --
00:44:15  Sending remote mail for firstname.lastname@example.org
00:44:15  Initiating connection to 18.104.22.168
00:44:15  Connecting to 22.214.171.124:25 (Id: 1)
00:44:36  Exception connecting to 126.96.36.199 (Id: 1)
00:44:36  System.Net.Sockets.SocketException (0x80004005): A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 188.8.131.52:25
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Connect(EndPoint remoteEP)
at RelayServer.Clients.SMTP.ClientConnectionSync.Connect(Int32 connectionId)
00:44:36  Connection to 184.108.40.206 failed (Id: 1)
00:44:36  Bounce email written to 265202046.eml
00:44:36  Delivery for email@example.com
has completed (Bounced)