Browser console log returns error 403 when browsing Jenkins UI components

Article ID:360032918931
1 minute readKnowledge base


  • We are unable to see a component in Jenkins. When we check the log, we see an error of "traits.js" failing to be retrieved, making a 403 forbidden in the console.


Check if CloudBees Request Filter is enabled and see the regular expressions attached to it.

The following one causes the crash:


1.- Go to Manage Jenkins > System Configuration

2.- Scroll down to Request Filtering

3.- Check if the rule is: ./api/\w+(?!.+tree=.+). If it is, it is likely filtering the api/ URLS, thus, failing to retrieve the traits.js what causes the 403 error and prevents you to see components, such as dropdowns.

4.- Delete it, or change the regular expression to one that allows the API to pass and blocks the desired ones.

If the problem persists, please open a support ticket including a Support Bundle, including all the Configuration options, such a Jenkins Root Configuration