We had an issue similar to this. After an IF install, we noticed this in our logs. We opened a PMR and were told by IBM to check the logs for network latency issues between Traveler and our backend Domino mail servers. You want to look for this in your stats (tell traveler stat show) output: DCA.DB_OPEN.Time.Histogram. If you see instances of open times over 120 seconds, that's a red flag.