IOS keep asking password with nginx auth_basic

[tiendungitd]

Hi there,
I'm using nginx auth_basic "Restricted area" to protect website. So users
have to enter user/pass one time to access, it work fine in computer.
However, When testing with Ipad, everytime access to particular page which
page extension is .ivp, it will require a credential, once I submit
user/password, I can continue to work in this website. I think my issue
similar to
https://stackoverflow.com/questions/6178507/mp4-in-safari-fails-with-htaccess-authentication,
but I did not using .htaccess to try with the solution mentioned in this
topic.

As you can see in access log https://pastebin.com/6vWhtb3Y, when I submited
a POST request, then browser will have GET request to ivp page, and got a
401 code which is require to enter user/password. Any idea of what might be
causing this?
Thanks.

Posted at Nginx Forum: https://forum.nginx.org/read.php?2,285874,285874#msg-285874