In the script runner guide here we show that the users may see an error that should provide them a link to click so they can accept the ssl certificate and open scripts in InteliJ.
It seems that something has changed and the error fails to show the link or the error itself has changed. Instead the users have to open the browser developer tools and find the link they need to go to in the console log.
This issue does not throw errors in the intelij log or the JIRA logs so I have only attached the screenshot that shows the GUI error and the console log output.
You need to clear your browser cache to trigger this if you have already accepted the ssl certificate once.
IntelliJ Ultimate 2018.2