Error HRESULT E_FAIL has been returned from a call to a COM component

delete web service reference and add it once a again.Find the “Web.config” file in Solution Explorer, and double-click on it to open it up. Once you’ve opened it, scroll to the bottom and look for the <services> section.

<service behaviorconfiguration="<br" mode="hold"> "AdventureWorks_WebServer.Service1Behavior"
name="AdventureWorks_WebServer.Service1">

<endpoint address="" binding="customBinding">
bindingConfiguration="customBinding0"
contract="AdventureWorks_WebServer.Service1" />

<endpoint address="mex">
binding="mexHttpBinding"
contract="IMetadataExchange" />



Notice that there are two endpoint tags: the top one, which has an address=””, and the bottom one, which has an address=”mex”. We want to focus on the top one, with the address=””, as follows:

<endpoint address="" binding="customBinding">
bindingConfiguration="customBinding0"
contract="AdventureWorks_WebServer.Service1" />
In order to successfully communicate with the Silverlight client application, we need to change the binding to “basicHttpBinding”, and remove bindingConfiguration, as follows:
<endpoint address="" binding="basicHttpBinding">
contract="AdventureWorks_WebServer.Service1" />

delete web service reference and add it once a again.Find the “Web.config” file in Solution Explorer, and double-click on it to open it up. Once you’ve opened it, scroll to the bottom and look for the <services> section.

<service behaviorconfiguration="<br" mode="hold"> "AdventureWorks_WebServer.Service1Behavior"
name="AdventureWorks_WebServer.Service1">

<endpoint address="" binding="customBinding">
bindingConfiguration="customBinding0"
contract="AdventureWorks_WebServer.Service1" />

<endpoint address="mex">
binding="mexHttpBinding"
contract="IMetadataExchange" />



Notice that there are two endpoint tags: the top one, which has an address=””, and the bottom one, which has an address=”mex”. We want to focus on the top one, with the address=””, as follows:

<endpoint address="" binding="customBinding">
bindingConfiguration="customBinding0"
contract="AdventureWorks_WebServer.Service1" />
In order to successfully communicate with the Silverlight client application, we need to change the binding to “basicHttpBinding”, and remove bindingConfiguration, as follows:
<endpoint address="" binding="basicHttpBinding">
contract="AdventureWorks_WebServer.Service1" />