I can confirm i get the same response. ngrok is running, the forwarding tunnel address is correct and if I navigate to that address in my browser I am able to get both my json file and html file (the names in the .json file all match the respective file names).
Update: I found the cause but I don’t know how to get around it. Digging through the network requests I found that the request to ngrok is returning the “You are about to visit . This website is served for free through ngrok.com. You should only visit this website if you trust whoever sent you this link”. If I navigate to that url i only get it when I clear my cache or visit for the first time in a new browser. Not sure how to bypass this in jira
For anyone that finds this. Its related to this: Ngrok agent < 3.1 no longer supported (affects out-of-box experience with ACE for non-paid ngrok plans) - #4 by SeanBourke
I got around it using cloudflare tunnel which is free and has pretty much the same functionality.