CC danielbeck

https://github.com/jenkinsci/slack-plugin is not an update site URL.

I removed the slack jpi and directory from /var/lib/jenkins/plugins and restarted but that didn't fix the issue.

I still see jenkins.plugins.slack.SlackNotifier.xml in the root directory (/var/lib/jenkins/). I moved that to a temp directory (/var/lib/jenkins/temp/) and restarted but that didn't fix it - I still see slack plugin references in the fuddled page text.

Then - since we had imported a lot of maven jobs from the older version of jenkins I removed all of them and restarted again.

Nothing seems to work to resolve it.  Any suggestions for me?

Not resolved, should it have been closed?

As I wrote, the wrong URL is configured as an update site URL.

Plugin Manager, Advanced.

Thanks danielbeck that wasn't at all clear on your first response – thanks for following-up again - I removed that and it fixed the main error.

Now I get error:
There were errors checking the update sites:

MalformedURLException: no protocol: ?id=default&version=2.222.3

Do you know if this is still the valid url to set for the update-center default?

http://updates.jenkins-ci.org/stable/update-center.json

>> that redirects to http://mirror.xmission.com/jenkins/updates/stable-2.222/update-center.json
with an error SyntaxError: JSON.parse: unexpected character at line 1 column 1 of the JSON data

Do you know if there should be url values in hudson.model.UpdateCenter.xml, and what should those values be?

// # cat /var/lib/jenkins/hudson.model.UpdateCenter.xml
<?xml version='1.1' encoding='UTF-8'?>
<sites>
  <site>
    <id>http://updates.jenkins-ci.org/stable/update-center.json</id>
    <url></url>
  </site>
  <site>
    <id>default</id>
    <url></url>
  </site>
</sites>

I don't know how you managed to configure that but it should look like this:

<?xml version='1.1' encoding='UTF-8'?>
<sites>
  <site>
    <id>default</id>
    <url>https://updates.jenkins.io/update-center.json</url>
  </site>
</sites> 

The only correct choice is https://updates.jenkins.io/update-center.json unless you use a non-Jenkins infra update site. Whoever told you to use /stable/ is wrong.

For further questions, please use chat or the Jenkins users mailing list.

Please leave this closed.

Thanks danielbeck - that was the magic charm.