On Friday 1 October, Super Office Online experienced an incident that caused incoming mail to our service solution to arrive without any content in the content section of the email.
Email messages are received by our mail service provider as a MIME message and transmitted using the SMTP protocol. The message is then transmitted to our ticket service solution using an HTTP POST, where the body of the HTTP message contains the original MIME message.
On October 1st at 00:00 UTC +2, our mail service provider rolled out a modification in the transfer encoding of emails that changed the coding.
The HTTP message transmitted to our ticket service solution had a HTTP Header value indicating that there were no HTTP message body present. This resulted in our ticket service solution accepting the HTTP message, but not processing the message body containing the original e-mail message in MIME format. The effect of this in our ticket service solution was that an empty message was received.
The solution to the problem was twofold. Firstly, our ticket service solution was modified to accept misleading HTTP Header values indicating that no HTTP message bodies were present. This resulted in successfully receiving e-mail messages from our mail service provider. Secondly, e-mail messages that was not correctly transmitted by our mail service provider to our ticket service solution were retransmitted. This resulted in the messages that was previously received as empty messages were received as e-mail messages.
Our fault tolerance has been enlarged and work in a way to be more robust and prevent similar cases happening again.