ACT! needs to be configured to use the correct URL, username, and password for CommuniGator. If the login is entered incorrectly or is ever changed, the ACT!  settings need to be updated.

This is updated in the config file which can be found in the following location:

C:\Program Files\ACT\Act for Windows\Plugins

And should be called:

CommConfig.xml

The username and password needs to be corrected in the file and then the file put back, if you are unsure about editing your config file please forward the file and your username and password to Support, who can do this for you.