Confirm that you are using the email address connected to the account or invitation. Use the same sign-in method you used originally; separate sign-in options and password sign-in may not be interchangeable.
If you use a password, request a new reset message and use its newest link. If you use an invitation, make sure the invited email matches the account email.
If access still fails, contact the account owner first to confirm your invitation and location access, then contact support if needed. Never send support your password or verification code.