Your ROOT_URL in app.ini is https://git.cloudchain.link/ but you are visiting https://dash.bss.nz/open-source-mirrors/homepage/blame/commit/5d63b3d2122fe949ab07568ab98625f2bdafdeb8/docs/widgets/services/opnsense.md
You should set ROOT_URL correctly, otherwise the web may not work correctly.
The API key & secret can be generated via the webui by creating a new user at _System/Access/Users_. Ensure "Generate a scrambled password to prevent local database logins for this user" is checked and then edit the effective privileges selecting **only**:
Finally, create a new API key which will download an `apikey.txt` file with your key and secret in it. Use the values as the username and password fields, respectively, in your homepage config.