The intermittent service issue has surfaced again today and we believe that it has to do with malformed traffic which is sporadic in nature. We are 100% focused on this issue and hope to determine and eliminate its root cause as soon as possible.
This issue affects a portion of our customers, and is experienced as very brief periods in loss of SMTP connectivity. For example, today, there were about 5 times where connectivity could have been lost for about a minute or so each time. There was no data loss, and any message that was successfully relayed to our servers, was received and processed normally.
If this issue is causing you problems, one option is to setup your own local SMTP server which relays all of its mail to us. Then your applications can relay your email to us through your local server, which can buffer messages if there is any loss in connectivity at your end, our end, or anywhere in between. This is a good practice in any event and SMTP was designed for this. Having a local server is also good for logging and diagnostic purposes too.