Unable to authenticate with username/password

I’ve followed the quickstart for Ruby on Rails and can successfully authenticate with a social account (gmail). When I attempt to “sign up” a regular email/password, I get the confirmation email and the account gets created on the dashboard, but I cannot login as the user from the app. I receive the following error:

We could not reach the server. Please check your connection and try again.

I’ve made sure that my URLs are all present, and all other functions of the program seem to be working correctly (logout, etc…).

The information provided is not enough to provide a definitive answer; for example, that error can be triggered due to incorrect client application configuration (callback URL’s and origins), however, you did not provide the configuration you’re using nor information about the authentication requests (parameters values and endpoints) being sent that lead to this issue.