Hi Folks,
We are working on to deploy Jenkins on new server(on new Datacenter), Jenkins is up & running but when we try to modify anything inside manage/system option & click on apply button it gives below error:
A problem occurred while processing the request Logging ID=6522151c-a050-412a-b7c6-161b75940afc
And when we click on Save button we get below error.
2025-05-08 10:01:52.492+0000 [id=195] WARNING h.i.i.InstallUncaughtExceptionHandler#handleException: Caught unhandled exception with ID 6522151c-a050-412a-b7c6-161b75940afc
java.net.ConnectException: Connection refused
2025-05-16 13:53:19.584+0000 [id=40] WARNING h.i.i.InstallUncaughtExceptionHandler#handleException: Caught unhandled exception with ID 5f2844be-d0ab-4819-bd09-cfa6640dc996
java.net.ConnectException: Connection refused
Observation -
Issue occurs when we modify anything in system option inside manage Jenkins.
We are able to make changes in other options eg., Credentials, Cloud etc(inside manage Jenkins).
When we click on both (save & apply) button, It is generating 2 different Logging ID but giving same Issue, Ideally it should show same logging ID (Could you please confirm).
When we make some changes & click on Save button it logs me out & redirect to configSubmit page with issue(Attached Screenshot) but note here is, it is able to save the changes & we could see those changes when we again go inside system option.
FYI, Jenkins is working as expected on current server, Only issue is on new server
Could you please suggest here, what could be the issue here??
What version of Jenkins is installed on the new server? (Compare with the old server.)
What is the exact Java version (java -version)?
What OS (and version) is the new server running? (Is it the same as the old server?)
2. Network & Connectivity
Is there a proxy or firewall between users and the Jenkins server? (The Connection refused error suggests connectivity issues.)
Is the new server air-gapped or behind stricter security policies than the old one?
Can you confirm if Jenkins is trying to connect to an external URL (e.g., update center, plugin site) when saving system configs? (Check Manage Jenkins > Plugin Manager > Advanced > Update Site.)
Are there any DNS or hostname resolution differences between the old and new servers? (Check /etc/hosts and DNS settings.)
3. Jenkins Configuration & Storage
How is Jenkins installed? (War file, Docker, native package, etc.?)
Is Jenkins running behind a reverse proxy (Nginx, Apache, etc.)? If yes, are the proxy settings correct?
Where is Jenkins storing its data (JENKINS_HOME directory)? Is it the same as the old server?
Are there any differences in the config.xml or other system files compared to the old server?
4. Logs & Debugging
Are there any additional errors in jenkins.log or syslog around the time of the issue?
Does the issue occur when modifying any system config or only specific ones (e.g., Jenkins URL, SMTP settings)?
Can you check if Jenkins has write permissions to its JENKINS_HOME directory? (ls -l /path/to/jenkins/home)
5. Authentication & Security
Is Jenkins using the same authentication/security setup as the old server? (e.g., Matrix auth, LDAP, etc.)
Are there any differences in CSRF protection settings? (Check Manage Jenkins > Security > Prevent Cross Site Request Forgery exploits.)
6. Plugins & Dependencies
Are all plugins the same versions as on the old server? (Sometimes plugin conflicts cause such issues.)
Does disabling plugins (temporarily) resolve the issue?
7. Browser & Session
Does the issue happen in different browsers or incognito mode? (Could be a session/cookie issue.)
Are you accessing Jenkins via HTTPS? If yes, is the certificate trusted?
Suggested Next Steps:
Compare old vs. new server configurations (Java, OS, Jenkins version, plugins, network setup).
Test connectivity from the Jenkins server to external resources (curl -v https://updates.jenkins.io).
Check for reverse proxy misconfigurations (if applicable).
Review Jenkins system logs for more detailed errors.
