No value accessor for 'username'

[brown14]

Thank you for posting this, I was getting the same error.

It seems that ionic 2 components aren’t playing well with the new Angular 2 form directives. I could get it to work with the basic html inputs.

They also discussed it in this topic:

Beta10 on AngularJS 2 RC3 Forms

You need to use regular input tags. Beta 10 has been released too soon. Still a branch on my project, too many bugs