Recently I had to reset my password, but when I copied and pasted the password from the html-formatted email that the server sent, that was rejected.
Maybe some hidden character came along for the ride when I double-clicked to select before copying?
Then I remembered that this had happened to me a few years ago, and the workaround is to view the email in plain-text/raw-message mode in your email client and copy the password from that -- which works.
If it's not obvious how to view the password-reset email in plain-text/raw-message mode, another possible workaround would be to paste the password into a plain-text editor (such as Notepad on Windows), then copy it again from there before pasting into the password field for the RHP login.
OK, sure, a third workaround method would be to move your email into a separate window (if using a web email client) so that both it and the RHP login are visible at the same time (or memorize the new password if you have that talent or skill), and just accurately type the new password into the password field.