"Allow Arbitrary Loads = true" not working

My App has In-App Browser. I used `WKWebView` for providing a Browsing feature within the app. So, currently, whenever a User is opening PDF in WKWebView it gets rendered within the WebView first and then if he/she wants to download, we have provided an option to download the PDF where we're making a separate download task call using

+ (NSURLSession *)sessionWithConfiguration:(NSURLSessionConfiguration *)configuration delegate:(nullable id )delegate delegateQueue:(nullable NSOperationQueue *)queue;

Now, the issue is with the download part where I am making a separate request. If user tries to download any file which is HTTP based, the download task gets failed with below error:

{"info":"Error Domain=NSURLErrorDomain Code=-1022 \"The resource could not be loaded because the App Transport Security policy requires the use of a secure connection.\" UserInfo={NSUnderlyingError=0x600001fe36f0 {Error Domain=kCFErrorDomainCFNetwork Code=-1022 \"(null)\"}, NSErrorFailingURLStringKey=http://www.africau.edu/images/default/sample.pdf, NSErrorFailingURLKey=http://www.africau.edu/images/default/sample.pdf, NSLocalizedDescription=The resource could not be loaded because the App Transport Security policy requires the use of a secure connection.}","error":"NSURLErrorDomain","url":"http://www.africau.edu/images/default/sample.pdf"}

In Info.plist I have set

<plist version="1.0">

<dict>

<key>NSAllowsArbitraryLoads</key>

<true/>

<key>NSAllowsArbitraryLoadsInWebContent</key>

<true/>

</dict>

</plist>

So, I assumed that It should allow HTTP requests but, here Its not happening so, if anyone has any clue then please help.

Thanks in Advance!