Your primary Apple ID and password say example1@icloud.com is same as rescue mail address , the password for primary apple is forgotten and same with rescue mail address and you can't enter the Apple ID account , also answers for security questions / date of birth is not in your records .
in that case if you go to iforgot.apple.com and try to reset the password , you can't open rescue mail account as you don't know the password , the apple id is still active , but all methods are failing to enter the account .
For that always remember in future , if you create an Apple ID account the Apple ID address and rescue mail address and password should be different .
For this particular Apple ID account contact apple support , whatever the credentials they require provide them see this link https://support.apple.com/en-in/HT201232