Hi @arir,
Welcome to the community and good job in writing Jira applications. That’s great to hear.
We are investigating a few similar issues and are wondering if this could be related to ngrok now enforcing an authtoken to serve HTML content.
Would you be able to check if there problem is resolved after installing an authoken for ngrok?
You will need to sign up to ngrok and retrive the token from the ngrok dashboard following the documentation available here: Overview | ngrok documentation
You could also check if there is an ngrok.yml file on the computer in use, by default this would be saved in the /Users/<user>/.ngrok2/ngrok.yml on a Mac.
Once the token has been set, you’ll need to restart the ngrok agent by running npm start in the app folder.
If this is the problem, you should see a response like the following in the corresponding request for the https://<tunnel>.ngrok.io/activity request:
Let us know,
Caterina