This add-on is misconfigured. Contact the vendor for assistance.

I am trying to integrate JIRA cloud with bitbucket cloud.
I am following the link https://confluence.atlassian.com/bitbucket/connect-bitbucket-cloud-to-jira-cloud-applications-814190686.html to do it.
However, i am getting "This add-on is misconfigured. Contact the vendor for assistance." message from JIRA.
And "No add-on was found at that URL. We received a 404 from the server. Double check the URL or contact the add-on vendor for help." from Bitbucket.
Is this because i am using free version? I found the link of bug report but it has not resolved yet. https://jira.atlassian.com/browse/JRACLOUD-65466\\
Please guide me how to fix this problem.