In order to intercept HTTPS traffic from Firefox, it requires extra steps to install Proxyman CA into Firefox's Trust Store.

Install Proxyman CA to Firefox

  1. Open on Firefox and download the certificate to your Download folder is a local HTTP Server for strengthening the security. Please make sure Proxyman app is opening when accessing this domain.

2. Open Preference on Firefox (CMD+,) and open View Certificate window

3. Open Authorities Tab and select Import button

4. Select Proxyman CA, which you've downloaded and Trust all.

5. Reload your page that you need intercepting. Enjoy!