Looking at the status page vs the history. They list the Messaging as being the affected service out of 10 other services. Seems like a pretty lynchpin service and also the one affected the most just eyeballing the last few incidences in history.<p><a href="https://status.slack.com/" rel="nofollow">https://status.slack.com/</a>
<a href="https://status.slack.com/calendar" rel="nofollow">https://status.slack.com/calendar</a>