Wednesday July 15, 2020

Issue summary:
On July 15, 2020 from 4:55 a.m. PDT to 6:41 a.m. PDT, some customers experienced difficulties starting calls in Slack. We determined this issue was caused by a higher than expected load on a part of our caching infrastructure following the unarchiving of a channel with a very high number of members. This had an unforeseen side effect of failed queries on a database involved in starting calls.

The increased load returned to a manageable level without intervention, but we are actively investigating prevention and remediation steps in this area to avoid similar issues from happening in the future.

4:37 PM PST

We've resolved the connection issue that customers were experiencing earlier with Slack calls. Thank you for your patience while we sorted out this issue.

10:19 AM PST

Slack calls remain stable and we continue to look into the cause of the disruption earlier today.

6:25 AM PST

Our engineers are patching things up and Slack calls should be connecting stably at the moment. We're still investigating what caused the original problem.

5:56 AM PST

We're receiving reports of Slack calls failing for some people. Our team is on the case. Apologies for the disruption.

5:25 AM PST