Please follow these steps - if you are stil having trouble, email info@plankeapp.com.
1. Make sure you have the app downloaded on your phone (not computer or tablet).
2. Check your email for a login link from planke-app@firebase.com.
3. Click on the link within 5 minutes to be automatically logged in.
4. If you still have an issue, then uninstill the app --> restart your phone --> reinstall the app and try logging in again.
5. If you still have an issue, delete all old emails from planke-app@firebase.com and try again.