Last night on 2020-09-08 at 23:57 UTC some planned changes were implemented on our database infrastructure layer. Unfortunately this change introduced an unexpected and previously not observed incompatibility with part of the Lyyti Messaging tool.
This issue caused a number of email and SMS messages to not get sent between 23:57 UTC and 6:21 UTC. This affected both manually sent messages and previously scheduled messages that were to be sent during this time frame. The issue was limited to the Lyyti Messaging tool, and transactional messages (e.g. confirmation messages) were not affected by this problem.
After locating and mitigating the problem this morning on 2020-09-09 at 6:21 UTC, our team took action to have the failed (i.e. previously unsent) messages sent. The last of these affected email and SMS messages were successfully sent at 7:55 UTC, after which this incident was declared resolved.