A server to provide single sign on services. The server includes a processor and a memory storing an attempt table. The server, in response to receiving a first password for a user account, forwards the first password to an authentication device. The server determines that the first password is not valid for the user account. The server stores the first password in association with the user account in the attempt table. In response to receiving a second password for the user account, the server determines whether the second password matches the first password. When the second password does not match the first password, the server forwards the second password to the authentication device.