Read the statement by Michael Teeuw here.
Password protection in mailbox.org calender link
Re: Problem with calender
I managed to display my calender from the provider mailbox.org. To increase security I would link to use the option of my provider to protect the link with a password but I don’t know which auth method to use in MM-Calender config, any suggestions?
In the settings of the provider I can choose a password but no user.