This problem has been resolved.
Customers might have experienced delayed responses when sending and receiving SMS via SMS API. Also, a small number of 504 responses were returned during the impacted timeframe.
Services were impacted from 2021-04-03 08:50 UTC to 2021-04-03 09:33 UTC.
All services have been restored.
Please let firstname.lastname@example.org
know if you continue to experience problems with this.