not able to get yubikey to work on iphone

Dave, I understand about that I only need to use it once on a device. i was told that when I was confused about not being asked each time to touch the yubikey. I used an older nano key that I used with dashlane. I purchased a second Yubikey, 5CI for the iphone. I am able to get on to 1password on the phone without the yubikey. But when I sign on, it does says "choose how you would like to sign on to 1password" and offers the choice of a passkey or a security key. When I check security key, and press continue, it says "use security key", and underneath that it says "no credentials for 1 password on this security key". I am very confused and not sure what to do. I don't need to use the it with 1password.com. I seem to have the password saved in 1password on the browser. Maybe that is not safe to have it there.