Register and Sign Up have no error treatment

[alaxalves]

Description

If you Register or Sign Up using wrong credentials or whatever there is no way of knowing you've input wrong credentials.

Expected behavior

Should display error messages.

Current behavior

No error message

Steps to reproduce the behavior

Try to Register or Sign Up using wrong/invalid credentials

Checklist

• [x] This issue has a significant name.
• [x] This issue has labels.
• [ ] This issue has screenshots (if necessary).

[danielmarquesr]

Solved in pull request #365.