Emails to internal accounts not being recieved

Emails to internal accounts not being recieved

i have sent emails from jkernes@certecinc.com to jmehta@certecinc.com and they do not arrive.  i can recieve them from jmehta@certecinc.com be he cannot recieve my emails.  I sent jmehta one through a different email account (AOL) and jmehta recieved it.