curl -i http://localhost:5000 I get a 403 Forbidden error.

I am experiencing this as well

I'm developing locally using Postman and Jetbrains Rider IDE and am getting this also.

HTTP/1.1 403 Forbidden
Content-Length: 0
Server: AirTunes/566.30.1

I haven't found a resolution. It seems to happen intermittently. I'm going to update the OS with the latest update and try again.

I figured this out. Monterrey has Airplay Receiver listening on Port 5000. You can disable it in System Preferences => Sharing => AirPlay Receiver.

Here is more info.

https://developer.apple.com/forums/thread/682332

It's possible that the upgrade to Monterey caused some changes to your network settings or security settings, which could be causing the issue you are experiencing with Postman and curl. Here are a few things you can try to troubleshoot the problem:

• Check your firewall settings: Make sure that your firewall settings are not blocking incoming connections to your application. You can check your firewall settings in System Preferences > Security & Privacy > Firewall.
• Check your application settings: Make sure that your application is configured to allow incoming connections on port 5000 You can check this in the settings or configuration files of your application.
• Check your network settings: Make sure that your network settings are configured correctly, and that your computer can connect to the internet and to other devices on your network.
• Try running your application on a different port: If you are still having trouble, try running your application on a different port and see if that resolves the issue.
• Check for any updates or changes to your application or dependencies: Make sure that your application and any dependencies are up to date, and that there have not been any recent changes or updates that could be causing the issue. Source: https://localhosts.mobi/5000