You can troubleshoot using 2 ways:
Using -debug argument in Selenium Grid
You can use -debug argument to print debug logs to console. Start Selenium Grid Hub or Node with -debug argument. Please see the below example:
$ java -jar selenium-server-standalone.jar -role hub -debug
Using Log Files in Selenium Grid
Also For advanced troubleshooting you can specify a log file to log system messages. Start Selenium GRID hub or node with -log argument. Please see the below example:
java -jar selenium-server-standalone.jar -role hub -log logfilename.txt
Use text editor of your choice to open log file ) to find “ERROR” logs if you get issues.
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