We are very sorry that you're having difficulties logging in to Doodle.
It may be that you have already registered using your Apple ID login and that you have selected for your Apple ID to be hidden.
Please follow the instructions below to find your hidden Apple ID:
On your iOS device (iPhone/iPad), go to Settings
Click on your Name at the top
Then go to Passwords and Security
Click on Apps Using Apple ID
Scroll down the list and select Doodle
You will see that "hide my email" is enabled. Your hidden Apple ID will be shown below.
You will then be able to use this to log in