Trying to sign on to iCloud in chrome -- not recognizing ID

I'm trying to log into iCloud via Chrome (on laptop). I've done this before but now after i allow all requisite security stuff (codes and whatnot) it asks me to verify my email. However, when i put in my email it says i can only use the @me.com email registered with the account. *I know what the email is*... I can access everything on my phone and a Mac. I've tried @icloud.com (The application type specified is unacceptable) and the my apple itunes/store ID (different from icloud) and get a different message (This email address is not available. Choose a different address). Not sure what's up but i have no other emails registered and, again, i know what the email is -- have had it for 10 years if not more. Thanks