I have followed the instructions per this article:
https://community.atlassian.com/t5/Bitbucket-articles/Atlassian-supported-Jenkins-integration-for-Bitbucket-Server/ba-p/1148326
The webhook is automatically created in Bitbucket upon saving the Jenkins Project configuration. The URL endpoint it creates is:
http://<url>:8080/bitbucket-server-webhook/trigger
Upon pushing a commit, the webhook triggers, but always errors with the timeout message:
java.net.SocketTimeoutException: 20,000 milliseconds timeout on connection http-outgoing-364 [ACTIVE]
(the number after http-outgoing- varies but is always 3 digits)
I get the same timeout error if I try to test the connection from the Edit Webhook page.
I've tried both an instance of Jenkins running in Docker and a fresh install directly on a machine running Ubuntu 18. There are no firewalls in the way. Jenkins has no problem retrieving and building from Bitbucket if I start the build manually.
Any ideas?