How can I connect GitHub to JIRA when 'unauthorized'?

Question

When I go to [my_jira]/plugins/servlet/ac/com.github.integration.production/github-select-product-page, and select Github Cloud, then open the blocked popup, it redirects to the URL https://github.atlassian.com/github/configuration and all that page displays is 'Unauthorised'.

Not sure what step I've done wrong, my Github has an organization, I can even see the repo in the <code> section of my JIRA board. I just can't seem to create any linkages from tickets, it keeps redirecting me to the github-select-product-page.

C L_b684rg · Answer

I connected the two with a Github Fine-grained Read-only Personal Access Token (that has since expired). I can't remember exactly where in the process I was prompted for this though.

Uche · Answer

What permissions do you have in Github? Are you an admin there also? It should prompt you to install an app on the github end that Github requires for the Jira connection

C L_b684rg · Answer

Here's the screen I start from, when I select "Continue" and open the popup...

... and this is the screen I get redirected to, other than the 'Unauthorised' text it's blank.