Enable debug mode

1. Switch into admin mode of JIRA and select menu item "System".
2. Select item "Logging & Profiling" within section "TROUBLESHOOTING AND SUPPORT"
3. Scroll down to section "Default Loggers".
4. Click on "Configure" logging level for another package.
5. Enter "de.syracom" as package name.
6. Select "DEBUG" as logging level, which is the default value.
7. Click on the "Add" button.
8. (Re-)try your action to get more detailed information within your JIRA log file
9. Detect your JIRA log file by default named "atlassian-jira.log" if not modified during setup: generally, it is located within folder "/log" within your JIRA home-directory.
10. Open the JIRA log file with any text editor and search for errors, warnings as well as debug information of status-sync (often, permissions are not set properly to execute related workflow transitions etc.)

Do not forget to revert the debug mode to warn or error level in order to prevent JIRA log file from being flooded with too much information.