Cannot log in

I was using this app on my android perfectly. About 3 months ago I switched to ask iPhone and I cannot log in. I click to login with an email and it says it already exists and to try to log in with Google or Facebook. I try with either of those and it says there is no account try using your email. Ugh. I really wanted to use my free coffee

Jeweliek about McDonald's, v5.4.0