When attempting to start LISTSERV, Windows error 2140 is thrown and LISTSERV does not start.

See above. The error literally means that the service did not start. You should check the LISTSERV log for specifics before contacting support.  Typically this happens because you do not have a current license or that your license capacity has been exceeded. Rarely, this error can mean something else is wrong; if you do verify that the problem is not with the LAK, contact the appropriate support address.