The situation sounds straightforward though there is no way for the OP to know this.

When you get a co-branded card from Amex, Amex opens a new Honors account for you. When they do this they very often do not add your email address to your account. (Neither do they add your phone number, but that is less important when it comes to getting online access to your account.)

There are two ways to fix the issue: 1) Call Amex and ask them to add your email and your phone number to the account. Once that is in place, go to the log in page for Honors, use your Honors account number as your user Id and use the 'forgot' password feature. The system will send a password reset email to the account Amex entered and you can set up a password.

2) Call Honors customer care and ask them to add your email address. When they see an account without an email address or phone number newer reps may throw their hands up and say they can not help you. (The standard ID procedure requires the caller to quote their name exactly as it appears on the Honors account and then two of the Honors account number, the email address on the Honors account or the phone number on the account.) In fact agents can also verify your identity and add your email address by verifying the name of the company that opened the account for you and the exact number of points in the account. (Amex can tell you how many points they transferred and that info maybe on a statement from Amex.) . If the Honors rep says they can not verify your identity, ask them to transfer you to the Verification Desk. Another option is not to call Honors but to chat with them. The chat reps are more experienced (and generally brighter and more willing to be creative) than phone reps.

Final note: if you opened new accounts on your own thinking that that might be a way to get access to the points Amex deposited, the email addresses you used on those accounts can not be used on the account Amex opened. (Two Honors accounts can not generally share one email address.) . If you are in this situation and there are no points in the accounts you opened, have the rep close them so that they can use the email address. If there are points on any account you opened that is using the email address you want to use on the account that Amex opened, ask the rep to merge the account you opened into the account Amex opened and then to add the merged account's email address to the account Amex opened.