Please follow this guide in your Jira DC instance.
Prerequisite
Please make sure that the server in which your Atlassian products run has access to the following domain: https://login.microsoftonline.com
This is a necessary step in order to validate the SharePoint users that are going to access the SharePoint Connector’s APIs.
Configure Allowlist
In order for SharePoint to communicate with Jira, you need to allow access from the desired SharePoint domain. Please refer to the documentation here on how to do this.
Please use the domain name Expression type with your company’s SharePoint URL, i.e. https://contoso.sharepoint.com.
Please make sure to tick the Allow Incoming option to allow CORS requests
Create application Link
The SharePoint connector needs to use an Application Link in order to be able to access the Jira APIs. You can read more here.
Follow this steps to configure a new Application Link for our app.
Go to Administration -> Application links and click on Create Link
...
Configure it as follows
Name: choose any name, i.e. SharePoint Connector Application Link
Redirect URL: https://<your-jira>/plugins/servlet/senora/redirect
Permission: Write
...
Save
Configure Connection
Open Manage Apps tab
Open Configure Connection under the SHAREPOINT CONNECTOR FOR JIRA section
...
Copy and paste from the Application Link credentials both the Client ID and Secret in the relative sections
Save
Continue with the next step.
| Info |
|---|
If you would like to remove the integration, you can revoke access centrally by simply deleting the Application Link in the context menu in the Admin area  Please note that after you delete an Application Link, if you want to configure it again, every user need to first logout from the application in SharePoint. |