Thursday November 8, 2018

Technical Summary:

On November 7th at 12:17 AM (PT), we began experiencing issues that prevented some users in Europe from successfully connecting to their workspaces over the course of two days.

These connectivity problems were caused by unexpected resource limitations in two European data centers.

We have been working with our upstream service provider, AWS, to understand why this has been isolated to these two regions. In order to reduce disconnections, we have performed the following mitigation steps:

• We have deployed additional hardware into the pool to distribute connections across more machines.
• We have converted one of these regions to work across multiple availability zones, which was done before the beginning of Europe's workday on November 9th.
• AWS has put a mitigation in place for the load balancers.

We are deeply sorry for the disruption this has caused to your workdays. Please let us know if you are still experiencing any connectivity issues at feedback@slack.com.

12:45 PM PST

We've resolved the connectivity issues affecting folks in Europe today. Everyone should be able to connect to their workspaces, and we'd like to thank you again for bearing with us.

3:40 AM PST

Our investigation and monitoring continue. We don't have any news to share as of now, and we thank you so much again for your patience.

3:13 AM PST

We don't have any further updates right now, but we are continuing our efforts to investigate these issues further.

Thank you again for sticking with us today.

2:40 AM PST

Our engineers are still looking into today's connectivity issues.

Thanks again for bearing with us, we really appreciate it.

2:09 AM PST

We are seeing some positive signs, and we believe folks should be able to connect once again to their workspaces.

However, our team is still digging into the root cause of these connectivity issues from today and yesterday, and we will give updates on our progress as news become available. We thank you for your continued patience.

1:37 AM PST

We've no new information to share just yet about the connectivity issues in Europe today, but we're working on getting things back to normal as soon as we can.

Again, we truly appreciate your patience.

1:06 AM PST

We are investigating reports of connectivity issues in Europe.

We're very sorry for the disruption, and thank you for your patience.

12:35 AM PST