This is what you need to do to fix this issue :
- Make sure your mup.js file is correct (Meteor Up - Documentation).
- Check if each of your
proxy.domains in your mup.js file redirects to your server.
- Run mup setup and mup deploy to deploy your app on your server.
- Run mup proxy setup and mup proxy start to configure and start the reverse proxy.
Your website should be now accessible in HTTPS !