WKWebView in application fails to get the authentication challenge

Hi,

We are facing an issue while browsing NTLM authenticating endpoints where our WKWebView does not get the authentication challenge. In the logs we see the following entry:

0x105d9c000 - [pageProxyID=9, webPageID=10, frameID=3, resourceID=87, isMainResource=0, isSynchronous=0] 
NetworkResourceLoader::didBlockAuthenticationChallenge:

and the CFNetwork logs failure to lookup the credentials:

default 2020-05-21 20:31:25.812654 +0300 com.apple.WebKit.Networking CFNetwork Diagnostics 
[3:16791] 20:31:25.777 { Use Credential: (null)         
Loader:  { URL: http://internalsire.qa/QG.Portal/PortalService.svc/$metadata }     Credential: null } [3:16791]

any suggestions what might be going wrong here. We can see that the 401 is written correctly to the WebKit but it fails later with the above logs.

Thanks.