Sender’s Sendmail says “stat=Sent” but recipent doesn’t receive the message

I am trying to figure out why sendmail is saying that it sends out an email but I actually never get it.

This is from the logs when the email is being sent out: I have replaced the email address with some fake address and I have also replaced the name of the server with a fake hostname.

The most significant point of this information from the logs is that it shows that the "Message was accepted for delivery".

Do you guys have any suggestions as to why it seems like the message goes out but I never get the actual email?

Jun  2 14:34:40 server sendmail[9668]: o52IYeSi009668: --- 250 2.0.0 o52IYeSi009668 Message accepted for delivery
Jun  2 14:34:40 server sendmail[9667]: o52IYe9I009667: to=someone@someone.com, ctladdr=rick (500/500), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30058, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (o52IYeSi009668 Message accepted for delivery)
Jun  2 14:34:40 server sendmail[9668]: o52IYeSj009668: <-- QUIT
Jun  2 14:34:40 server sendmail[9668]: o52IYeSj009668: --- 221 2.0.0 server.server.com closing connection
Jun  2 14:34:41 server sendmail[9670]: o52IYeSi009668: SMTP outgoing connect on [192.168.1.9]
Jun  2 14:34:41 server sendmail[9670]: o52IYeSi009668: to=<someone@someone.com>, ctladdr=<someone@server.server.com> (500/500), delay=00:00:01, xdelay=00:00:01, mailer=relay, pri=120368, relay=mailhost.worldnet.att.net. [207.115.11.17], dsn=5.1.1, stat=User unknown
Jun  2 14:34:42 server sendmail[9670]: o52IYeSi009668: o52IYgSi009670: DSN: User unknown
Jun  2 14:34:42 server sendmail[9670]: o52IYgSi009670: to=<rick@server.rickrodriguezjr.com>, **delay=00:00:00, xdelay=00:00:00, mailer=local, pri=31625, dsn=2.0.0,** ***stat=Sent*****