This problem was submitted to us by one of our readers who came across the following error message “You have been disconnected from chat because you have signed into Yahoo Messenger from another computer or device”
Well there is nothing to be afraid of as this error message is common and can occur because of logging into different clients at the same time.
Cause of the problem:
If you are using the new Yahoo Mail with Chat feature and also logging at the same time on the desktop Yahoo Messenger client then you can’t log into both at the same time, hence the online email with chat feature disconnects and comes up with the message.
It’s a conflict between the yahoo mail server and the yahoo messenger server. You must disable chat in your Yahoo Mail if you want to use your desktop Messenger, by doing the following:
See the smiley face next to your user name at the top of the mail page? Click it – then click Sign out of chat. You will remain signed out for every session of log in until you change your status back.