Pass USER TOKEN when IFRAME occurs - by: frozo

Hi, what i want to do is to pass token throught iframe. I tried this:

maiten.com/encuesta-utilizacion-del-serv...lang=es&token={TOKEN}

When a user receive email invitation where is {TOKEN} changes to his/her user token, but It does not work because the system requieres the passwrod. Please seee this print screen: prntscr.com/ciaakb

As you can see in print screen, in LINK URL appears the USER TOKEN (sent by email) but the survey does not recognized it, so it requieres a password. How can I get to do it? Help me please