From TN 1507380
Domino server 8.5.2.3 (Fix Pack 3) changed one of the API calls that the Lotus Traveler server uses. Running Domino 8.5.2.3 and Lotus Traveler 8.5.2.3 (or lower Fix Pack level) can cause a server crash scenario.
Traveler 8.5.2.4 (includes APAR LO62635) is available from Traveler Recommended Maintenancepage.