can not call web service in visual studio .net

i try to call web service in Microsoft visual studio .net but i got an error

Could you advise please..

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There was an error downloading 'http://NAVSVR:7047/DynamicsNAV/ws/Cronus_International_Ltd'.
The request failed with the error message:
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<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"><s:Body><s:Fault><faultcode xmlns:a="urn:microsoft-dynamics-schemas/error">a:Microsoft.Dynamics.Nav.Service.WebServices.ServiceBrokerException</faultcode><faultstring xml:lang="en-US">Service "Cronus_International_Ltd" was not found!</faultstring><detail><string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">Service "Cronus_International_Ltd" was not found!</string></detail></s:Fault></s:Body></s:Envelope>
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Metadata contains a reference that cannot be resolved: 'http://navsvr:7047/DynamicsNAV/ws/Cronus_International_Ltd'.
The HTTP request is unauthorized with client authentication scheme 'Anonymous'. The authentication header received from the server was 'Negotiate'.
The remote server returned an error: (401) Unauthorized.
If the service is defined in the current solution, try building the solution and adding the service reference again.