The Red Gate Check for Updates service, available through the Help menu of most Red Gate products, may fail to connect to the Red Gate update service if internet access goes through a proxy server that requires authentication.

The Check for Updates service uses SOAP to communicate with a web service hosted at update.red-gate.com on TCP port 80. The service supports connections through an HTTP proxy as long as the proxy server integrates with Internet Explorer and has been properly configured in Internet Options > Connections (available from Internet Explorer or Windows Control Panel). In other words, Check for Updates uses Windows WinInet API to send and receive requests for updates.

If the proxy server doesn't integrate with Windows and doesn't support transparent NTLM authentication, Check for Updates will prompt you for a proxy username and password and try to authenticate using Basic Authentication. Finally, the request will fail with the message "could not connect to the update service".

Even when WinInet is properly configured for your proxy server, there are two known circumstances that may cause Check for Updates to fail:

• An automatic configuration script is used to configure the Internet Explorer proxy connection. In this case, the connection properties can be configured differently for every connection. This can cause Check for Updates to behave erratically, sometimes being able to connect and sometimes not. 
• A bug in some versions of Check for Updates whereby any proxy server that doesn't have "realm" configured will cause Check for Updates to crash. Contact your proxy administrator to make sure a realm is configured in the authentication settings.