Before installing the messenger plugin, messages were sent from my support email, [email protected] , now that I have installed the messenger plugin they are sent , [email protected] , what do I need to change for all messages to be sent [email protected], or "My Site Name"@mydomain.com.

@Sparky
Configure your mail server in Settings > Mail server

 I configured my mail server in my settings, but it did not change anything.

 Without my mail server configured and without messenger installed, using the contact button,  I get messages sent as they should be:
 NwaMarkets - Someone has a question about your listing
 from,  NwaMarkets <[email protected]> ,

 With or Without mail server configured and messenger installed and Contact seller functionality turn on , I get email messages sent to me like this:

 [NwaMarkets] New message: Cadillac Rims
 from,  NwaMarkets<[email protected]

This email as sender is only used, if not defined in mail server settings

 I finally got it figured out in the mail server. Thanks.

Cool