HTTP 1015 - The authentication method requested is not supported RespHdrGetHdr
This error is thrown in Silk Performer version 10 and below when using NTLM authentication in combination with any browser which is not an Internet Explorer or Custom type. The reason for this is that historically only Internet Explorer supported NTLM so for realism a check was added to ensure that if a user tried to simulate NTLM authentication with an unsupporting browser an error would occur as this is not a valid combination. Most browsers now support NTLM authentication so this error is no longer valid.
This behaviour will be resolved in a future version of Silk Performer. Currently the issue can be resolved by selecting any of the IE versions or custom in WebSetBrowser function or in SETTINGS | ACTIVE PROFILE | WEB | BROWSER.