You said “2 days ago the changelog stopped coming back” so, if that endpoint was returning changelogs prior to then, then it stands to reason that something has changed, so I’m asking you questions to determine… WHAT CHANGED TWO DAYS AGO?
- Have you liaised with your organisation’s IT department FIRST with this problem?
- Is this happening for all issues in all projects?
- Are you the only person in your organisation experiencing this problem?
- What language / library / toolset are you making this request with?
- What scopes did you use with the OAuth request?
- Have you tested the same endpoint with a Basic auth request as well?
- What testing have you done with your API test tool?
…etc etc etc etc
Refer to the How to ask a good question thread for an overview of the bare minimum level of information you’ll need to provide for anyone to be able to assist you.
Lastly, and probably most importantly, your screen grabs shows you are making an OAuth request to a Jira CLOUD instance, not a Jira DATA CENTER instance, so you’re referencing the wrong documentation, as that’s a totally different product, and you’ve put the wrong product tag on your question, so that’s added to the confusion.