chances are that i just did something wrong, but i think there is a bug in the wordpress plugin.
When I embed a private model in a wordpress blog with the sketchfab plugin i am asked for the password as expected, but when i enter the correct password and press Enter or click on Ok nothing seems to happen.
A Post to https://sketchfab.com/models/3437e9fd0a9e4d9493e8afd6bcd65a61/embed/password?autostart=0&autospin=&controls=1&transparent= is made and returns Statuscode 200 but im still presented with the input box where i can enter the password:
This is not the case when i have a regular embeded viewer (via oembed). What is funny however is, that setting the password seems to work. Because as soon as i open the same password protected model in another browser tab in a regular ebmbeded viewer it shows the model. So i suppose the auth cookies have been set. Once i have seen the model in the second tab i can reload the first tab (with the wordpress plugin) and the model is showing.
To test this it is important not to be logged on to sketchfab and to clear cookies.
Hope this helps.