Any update to this topic? I’m currently trying to setup TestRail and JIRA (Cloud) integration. From JIRA I can see the test cases and test results, all that seems to be working correctly. But in TestRail, for example hovering over a defect, I get the same 502 error. I have the JIRA plugin setup and the integration key working, as I said I can see results from the JIRA Stories.
I also get the same error from the Defects list under the test cases, as well as if I try to Push a Defect from a test result.