Password protected Reels are generally the ones that you purchase, so contact who you purchased it from and ask them to supply you with the password.  It is impossible to load a Reel without the correct password because they are encrypted and the password is the decryption key.

Also, passwords are case sensitive so make sure you are entering it correctly.  For example, if the password was 'paSSword' then typing 'Password' would be incorrect, it must be typed exactly as it was when the password was issued to you.