Sockets on a computer are connection points between programs. This normally occurs with two different machines, but sockets can also be used to connect one program to another. During this connection, a socket error 11004 can occur. This happens when someone has to log into a system such as an email or website server. For this error, the name is right, but the server is not returning the right information, so the login is denied because a firewall or incorrectly configured server is blocking the correct access.
As with all socket errors, the use of a firewall or antivirus software can cause the socket error 11004. Firewalls are responsible for ensuring that all access to and from the computer is regulated. This means errors can occur because the firewall is not granting access when it is required. It is best practice to disable any firewall or antivirus programs, temporarily, to see if the computer can connect to the server without the error.
More often this happens because the domain name server (DNS) is not returning the right information for the Internet service provider (ISP) or thinks the computer is wrong. For the former, this means the DNS is showing that the name is correct, but the other information needed for the login is not coming up. In the latter case, the login information may be right, but the program shows the computer being used is different from normal, even if it isn’t, and may still deny access. If the problem is from either of these instances, contact the Internet provider and ask them to retrieve any lost information and fix the server.
Another reason for this problem is that the computer attempting to connect to the server is using the wrong DNS. For example, the user has two DNS systems, each with its own ISP. If the user attempts to use the second DNS for the first ISP, it either will not work or will return a socket error 11004. In this case, change the DNS information to the correct ISP.
If a server name from an ISP and an internal server name are similar then this problem can also occur. If the ISP has a server named Fred and the computer has an internal server named Ed, for example, then this can cause the socket error 11004. This is because the computer gets confused and uses the wrong information for the wrong server. To fix this, the user must manually tell the computer which server is which.