A subset of outgoing messages may have responded with "host not found" between 11:30AM and 11:32AM
While developing new changes on an outbound node, we noticed the load balancer did not pull the testing server out of rotation and temporarily allowed mail to relay through to the test server. Unfortunately, the outbound test node wasn't fully configured to handle routing from customers and responded with the following error
DSN: Host unknown (Name server: 127.0.0.1: host not found)
The test node was quickly removed from the network and we confirmed it was no longer in rotation before continuing development.