"The port was disconnected by the remote machine."

This error is pretty straight forward. It means that the computer/NAS/RAS you are dialing into disconnected or rejected you for some reason. Might seem straight forward but there are many many possible reasons for the error.

The most common reason for getting this error while trying to connect is username and password errors. Triple check to make sure you are tpying your username in correctly, no caps lock key etc. Even open up notepad, and type the password in there, just to make sure no keys are sticking etc.. Also make sure you are using the correct username, some ISP's make users use usernames that are their whole email address, some ISP's only use the first part of the email address as the username, doublecheck what yours is supposed to be using.

I would also just give your computer a quick reboot. Might sound funny, but it works on many occasions.

If you are sure that you are typing your username and password in correctly. There is the chance that the settings for your connectoid might be off, thus causing the problem. If you right click on the connectoid in Dial Up Networking and go to properties a friendly tech support rep from your ISP can walk you through checking the settings. In most cases, on the 2nd screen only TCP/IP should be checked, you usually don't need NETBEUI, IPX/SPX or log on to network.

You could also just use the documentation from your ISP that you hopefully have to create a new connectoid instead of going through the old connectoid.

For Windowd NT 4.0, in the phonebook, go to the security tab and make sure "accept any authentication including clear text" is checked (this is a common error).

There is a chance that under Network in the Control Panel, one of the settings might be off, again, check the documentation from your ISP about that. In most cases click the properties of TCP/IP (most common problems in those settings).

I'd turn the volume up on the modem, and listen to the connection, this is good information for your ISP's tech support. You will hear the modem tones, but at the end, you should hear a connection where it goes silent... and if it doesn't and just is an endless single tone, I'd suggest using an init string to lower your modem's speed, get online at the slower speed, then download newer drivers for your modem. You can also play with init strings to give your modem the higher speed but remain stable as well.

Again, check the phone cord for damage, use a different phone cord/phone jack, and check the line for static or poor quality sound.. The poorer the sound, the lower maximum speed you can achieve, and in many cases, this can stop you from getting a connection altogether. Init strings can be also be used again to tweak the connection speed and stability in some cases.

Last but not least, is your ISP, give them a call, maybe they are having a network issue, and that is the cause of your problems. It's very easy for there to be a line issue (PRI), or a power issue, or cut cabling, or a radius (authentication server that validates your username and password) not working or any number of other things that could cause problems. So I would always check with your ISP, they might have a message up on their queue when you call their tech support number.


Here is an official Microsoft Article on Troubleshooting this error.