The AWI 12.3.x Log that is stored in the logs folder of the Tomcat instance traces a lot of ERROR messages that do not cause any impact.
The messages look like this
[ERROR] NOSESSION/- NOUI [org.atmosphere.container.JSR356Endpoint]
and may appear very often in case of a Load Balancing Infrastructure with many AWI users.
Unwanted trace messages are stored by default in AWI 12.3.x as per logback.xml
Release : 12.3
Component : AUTOMIC WEB INTERFACE
These messages are in reality Warning traces that should not be displayed by default and that have no impact.
Most likely reason is that the websocket connection is being closed too fast from Load Balancer / HA Proxy.
The same thing happens in standalone sessions, when the session between browser and Tomcat is closed too soon or unexpected - browser is closed, session is closed, etc.
As a workaround, please disable this logging information in the AWI logback.xml file that is found in the config folder.
Please add/replace the following lines:
<!-- vaadin/atmosphere logs non-errors on error level, turn it off. If you experience any push/connection related problems, ena
ble this temporarily -->
<logger name="com.vaadin" level="OFF" />
<logger name="org.atmosphere" level="OFF" />
Then restart the Tomcat servers.
the logback.xml that will be delivered with next Major Release of Automic Workload Automation (20.0) will include these settings by default.