Error Accessing the Catalog Web Service

It is rather misleading in that it's not actually a problem with the web.config line 51 as indicated below, but is more an issue with your applicaiton pool identity. Check to ensure that the identity has the proper permissions to the Commerce SQL Database.

Error Message:

System.Web.Services.Protocols.SoapException: An error occurred creating the configuration section handler for CommerceServer/catalogWebService: Failed to get the connection string of the product catalog resource for the specified site.

(C:\inetpub\wwwroot\DefaultSite_CatalogWebService\web.config line 51)

<catalogWebService siteName="DefaultSite" authorizationPolicyPath="CatalogAuthorizationStore.xml" debugLevel="Production" maxChunkSize="1024" maxUploadFileSize="204800" timeOutHours="24" enableInventorySystem="true" disableAuthorization="false" maxSearchResults="500">

<cache enable="false" schemaTimeout="5" itemInformationCacheTimeout="5" itemHierarchyCacheTimeout="5" itemRelationshipsCacheTimeout="5" itemAssociationsCacheTimeout="5" catalogCollectionCacheTimeout="5"/></catalogWebService>