Solved
Failed to execute Zephyr test cases when execute hit button in Jira
When trying to execute the Zephyr test case from Jira it takes to the test cases repository page rather than execution.
I'm guessing that you're clicking the test case ID or test case description. You would need to click the 'play' icon on the right-hand side. You can see an explanation here: Agile Development | Zephyr Scale Server/Data Center Documentation (smartbear.com), but here's a screenshot of the 'play' button also:
