problem connecting to secure web service

I have developed a simple web service using asp.net web services on my local machine and have provided Windows Authentication in IIS server. When I run the service from browser, it asks me for the userid and password which when provided allows me to access the service. However when I try to do the same from SOAPUI (connecting to WSDL by providing userid and password), it takes forever to connect. What could be the issue here?

Thanks
Manik