We use a bespoke client to send emails through ISPConfig using SMPT. The client and ISP config are setup on different servers. The system was working perfectly before, but after recent upgrade of our client to run multiple threads we ran into issues. We were getting "too many connections" and "connection time out error" intermittently. After raising the default number of connections, the "too many connection" issue was resolved but we still are getting the "connection time out" error. What's confusing is that it's not a permanent error. Can any one help.
that's the server saying "connection timed out"? you might need to either montior the smtp traffic on the wire (if unencrypted between the client/server) or enable debugging in postfix for this client to see what's going on at the smtp level
