iOS11 safari prompts user/password box repeatedly

hi.

We have an web application which works on IIS,using Integrated Windows authentication.

Our application has an issue and we want any information about it.


detail:


(1)An user logs on our application using Safari in iOS11,and the login is successful.

(2)When the user move pages, Safari sometimes prompts for the username/password again.


In iOS12,this issue doesn't occur.


We found an information about similar problem.

https://stackoverflow.com/questions/46931988/ios11-basic-authentication-issue

Referring to this URL, we switched off the setting 'Prevent Cross-Site Tracking' on Safari.

But the issue is not solved.


Thanks in advance.