Use ?diag at the end of the URL when browsing to the sqlcesa30.dll to check connectitivity. This diagnostics tool provides information on the ability of IIS to connect to SQL Server. e.g. http://{your domain or server name}/reach4mobile/sqlcesa30.dll?diag The following links provide useful information for debugging RDA error codes. http://msdn2.microsoft.com/en-us/library/ms171849.aspx RDA Quick Check List (use this quick check list if experiencing RDA issues)