Logging into the app requires only you have access to the email you used for registration. If you are not receiving the email, the link in the mail does not work, or the app presents an error once you click the link, wait for 5 minutes and try again.
If after waiting you are still experiencing problems, please restart the app and phone and try again. If this does not work, please re-install the app.
When none of the above options fixes the problem, please sent a message to support@gropyus.com.