how to send a private message to a tech republic member?

Hi all

i posted a question someone answered id. and i tried to send a private message by clicking “Send private message” i got this this error
“Your message was not sent because your email address is either invalid or blocked from sending emails. Please contact a system administrator.”

i ensure that my mail id is valid.
Who is the Administrator in tech republic? how can i reach him?
please someone help me