Trigger Jenkins Job from Azure DevOps
The error message you have provided indicates that this is a problem with the configuration that could be permission related.  Here are some steps to help resolve this issue:


You can follow guides where other people have configured the two.  Pay special attention to the permission settings that are selected.
Double check your permissions on the servers.  While you may have configured Jenkins to communicate with Azure DevOps, you still need to make configuration changes in DevOps.
Double/Triple check your URLs on both systems.  I've been burned by dropping an s on http or missing a character on a copy paste.
If you are setting this up within Azure check the Azure Role Based Access Control to make sure proper permissions exist.