Agreeing with Netti, there are several possibilties so more information will be great. Additionally, If you are trying to access web messenger from work, then most likely you are running on a secure network that has a router/network hub/firewall system setup for security purposes. In this instance only those who have “administrator privileges” will be able to make the necessary changes in order to allow you to connect to messenger on the web. For questions about firewalls click here. For more troubleshooting information for Messenger Connection issues you can also visit http://help.yahoo.com/help/us/mesg/twin/index.html