Vantage has the MSGE0001 DD filled, causing the message "MSGE Logging Stopped. MAX Count Reached." to be displayed in the log.
The most likely reason for the MSGE to be full is that one or more users have logged on with the Host Trace set to YES in the Host Definition, or that one or more scripts have specified TRACE=Y in their General Section.
The host definition for Windows UI:
Host definition for Web UI: