If your browser uses saved logins then it's possible a previous saved password gets filled in to the password box.
Try entering both email address and new password manually and then updating the saved login. Assuming that the new password was accepted as valid when you went through the password reset process.
You can always try the Forgotten password journey once more. Tip: Don't try any password that has previously been used as the system will reject any of the last 5 passwords if you try to use them again.
The Reset password now button in the help article Changing your email password will take you to password reset and recovery. If you have set up password recovery options, in advance, that you recognise from the *****hints, then you can send your alternate email address a link or your mobile a 6-digit code to authorise a password reset.
