dSeries (CA Workload Automation) will stop sending mails, notifications, etc. Tracelogs will show the connection reset error:
Exception reading response; nested exception is:
java.net.SocketException: Connection reset
To immediately fix the issue, the user can do a CHANGEROLE and all the mails will start flowing. If client is running dSeries on a stand alone configuration, then the server must be re-started.
The dSeries server opens one connection to the mail server with no timeout setting. The server then relies on mail server to reset the connection. If this connection gets disrupted, but is not fully reset due to some networking glitches, then dSeries will not be able to send out mails. The 'HAC.emailNotification' thread then has to be re-initialized. When CHANGEROLE or restart is done, the mail connection is reinitiated and mails will start to go out again.
Customer should look in to their network to make sure that aren't software and hardware malfunctions. Customer may also look into some kind of traffic analyzer (sniffers, tcpdump) to monitor any unusual patterns.