This will NOT work with Obi 202, as mentioned on this forum.
If you have Obi 202- go to the expert configuration.> system management.> device configuration
In the web server area, check the box (on left, un check the box on right before that) > submit.
I rebooted the Obi after that, not sure whether it is necessary.
The default passwords are admin and admin, but if you want to leave it accessible from the internet, choose strong passwords.