Thank you for reporting this. It seems like a similar issue was raised a little while ago for the https://[servername]/api/users/me call however not the Jira call. This should mean that the next public release should rectify the 404 errors on devtools, however likely not the Jira issue.
I will replicate this in a fresh environment and send it off to the engineers to fix.
Just to confirm, you aren’t being blocked in any way from this issue?
Thanks for the response. I think I’m ok, I replayed the post with the correct url in devtools and it returns a 200 OK response, so I assume that means my jira connection is working.