Set the Name field for each of the input elements to match the name= field from your form code, i.e.:
First name field ( Name field = uname)
Password field ( Name field = pwd)
Set the form method to Post
Publish your site and test your form.
If your form submits successfully and posts the data, you should see a 200 OK connection in Network tab of the Developers console.
If the form data does not post, inspect your page elements and look at the browser console and see if there are any errors.
Webflow does not control the connection or ability to verify if an external system receives the data. Webflow does post form data using standard html form POST method.
Those are some things to check. I hope this helps !