Thursday September 13 - Saturday August 24, 2019


Issues receiving 2FA codes via SMS for Japanese customers

Technical Summary:
On September 13th between 5:05pm and 7:20pm Pacific Time, some customers from Japan were unable to receive SMS authentication codes for Slack. This was due to a temporary issue with an upstream provider which has now been resolved. Everyone who was affected should once again be able to receive codes and sign in to Slack. If you have any trouble, please contact us via

8:55 PM PST

Japanese customers should now be able to receive 2FA SMS codes once more. We're continuing to work with our service provider to understand the cause of the issue. Apologies for all that hassle.

7:20 PM PST

From our investigations this appears to be caused by an upstream provider issue and we will continue to follow up with them for a resolution.

In the meantime, you can talk to a workspace Admin or Owner to temporarily disable Two-Factor authentication. Alternatively, you could try using a 2FA authentication app — we have instructions on how to do so here:

Apologies again for this disruption to your day.

7:08 PM PST

We're digging into reports of some of our Japanese customers having trouble receiving 2FA codes via SMS. Please bear with us.

5:05 PM PST

Services affected