At 08:10 UTC on May 13th, 2020, customers started having issues with Outbound and Inbound SMS delayed for a number of European carriers.
In addition, at 08:37 UTC, Voice API and Messages API callbacks for requests processed by our European datacenters started to be missing.
A fix was applied at 08:56 UTC but the Messages API callbacks continued to be delayed for a few more minutes as we were reprocessing the queues.
Misconfiguration in the VPN tunnels used to integrate with our partners.
Improvements to our test suite to cover a wider variety of VPN settings and catch mistakes before going to production.