GSSAPI key exchange authentication is off by default as it caused failures when old version of MIT Kerberos was installed on the machine

https://winscp.net/tracker/1874
(cherry picked from commit dceed175a8cf8c726b91adbcce6afa1bb8596fd6)

Source commit: fed89fab168af600e6e13db7af5538b7aab5d130

source/core/SessionData.cpp

@@ -133,7 +133,7 @@ void __fastcall TSessionData::DefaultSettings()
   AuthKI = true;
   AuthKIPassword = true;
   AuthGSSAPI = true;
-  AuthGSSAPIKEX = true;
+  AuthGSSAPIKEX = false;
   GSSAPIFwdTGT = false;
   LogicalHostName = L"";
   ChangeUsername = false;