Can't trigger build on Jenkins although being logged in

November 28, 2023

We are running nearly latest Jenkins (checked here for ourselves and there is one stupid error that seems to be connected with security and how the Jenkins is setup so maybe you will not fall for this stupid thing too and save some time looking around wondering WTF is happening.


Just setup Jenkins to force to use https like described in the end here :

or you can tell your browser to use just use https automagically like this

When this problem happens

  • you are logged in and you want to trigger build and you have rights for that
  • your Jenkins is by accident opened as http and not https (and still you are logged in)
  • there was no other build triggered yet (so you see Build Now button)
  • when you click the Build Now button there is note “Build scheduled”
  • no visible error on the page

How my Build scheduled note looks like after which nothing happens (yes, just like if all would work but nope):

Jenkins build scheduled note

What is the problem

If you would open the dev tools you would see that this error happens but the UI will not tell you that (unfortunately).

This might happen if you have still valid cookie or “somehow” managed to get valid cookie that is not issued with property.

What would you see looking at requests to Jenkins when running over http:

Jenkins http only cookie

What would you see looking at requests to Jenkins when running over https (yes, the old http cookie plus all the Secure ones):

Jenkins https cookies

How to fix this

It doesn’t matter how you managed to get a valid cookie without Secure property, you should delete it and reauthenticate. If you will delete all cookies (for your Jenkins machine URL) and get a new one by authenticating, then if you would deliberately switch to http you would not be logged in altogether since the new cookie with Secure prop would not be sent. In the end you are more secure now.

Alternatively as said in tldf switch Jenkins to just use https OR switch your browser to https only mode.

Hope you saved some time.

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Written by Dušan Roštár - the "mr edge case" guy
my twitter : rostacik, my linkedin : rostar, drop me an email : here