Snowplow-Micro Blocked by CORS policy

I have managed to run Snowplow-Micro from Docker but I believe I have a configuration problem as when I run a little test app I wrote which uses a Javascript Tracker I get a CORS issue:

I was hoping someone could point out where the problem is?

Hey @DM_SP

This is because you’re trying to send the request from a file:// based URL which won’t be able to send a POST due to the CORS headers present.

You’ll want to start a small web server on your local machine to serve the HTML/JS files on your localhost which should allow it to start working.

Something like http-server is probably the simplest way of achieving this: http-server - npm

Another quick thing to check:
From the screenshot, it looks like your tracker is configured to send events to subdomain.domain.com, it seems more likely the endpoint of your micro is something like localhost:9090 - where the port is the number in your docker command: docker run --mount type=bind,source=$(pwd)/example,destination=/config -p 9090:9090 snowplow/snowplow-micro:1.1.1 --collector-config /config/micro.conf --iglu /config/iglu.json

Thanks Paul. I shall check out your suggestions.