I have the same problem, have been attempting to create an account and sign in since yesterday, but always get the same behaviour. After creating an account with an e-mail address, I receive a password by e-mail within 30-60 seconds, but on entering the password to gain access to the game I get the error message 'wrong credentials'. I have tried the resend password. I have tried uninstall and reinstall. I have tried creating different e-mails. I have tried iPad, Apple MacBook and Windows 10. I have tried creating an account and leaving it 30 minutes and 60 minutes before trying the password. Same result each time.
It seems a lot of people are experiencing this issue, and it is very easy to replicate. Please help.