...
Navigate to https://developer.atlassian.com/console/myapps/
Click Create → OAuth 2.0 Integration
Name the new connector (e.g. ZillaConnector), agree to terms, and click Create.
On the side menu, click Permissions and add the following.
Jira API - click on add and then configure
Click on Edit Scopes and select
read:user:jira
: View usersread:application-role:jira
:read:avatar:jira
read:group:jira
On the side menu, click Authorization → OAuth 2.0 (3LO) config (click on configure)
Enter in Callback URL: https://app.zillasecurity.com/api/auth/callback/jira and click save.
On the side menu, click on Settings and scroll down to view Client ID and Client Secret.
Copy these values in Zilla to configure JIRA.
...