We are running an NT Server with Small Business Server 4.5. Every day clients have trouble getting onto the internet via the proxy. If you try to dial the phone book entry on the server the following message appears: RAS Error 633: The Port is in Use or Not Configured. Microsoft Technet suggests upgrading to the latest service pack (article Q162807), but installing SP6a has yielded no results. Stopping and starting the RAS service and switching the modem on and off also makes not difference. Intask manager, nothing seems to be hogging the port (VNC is disabled). The modem is using the unimodem driver supplied with NT. The only way to get the port back is to reset the server and doing that once or twice a day is not really a solution. Any help would be greatly appreciated.