New Member Not Receiving Opt In Email

Our club has a new member, his email address is xxxxx@sent.com. For some reason he is not receiving opt in emails. I've asked him to check his spam and provide another email address. The second email address he provided was also xxxxx@sent.com, and he is still not receiving the opt in email.
I tested with a gmail account and received the opt in email, so I'm sure the functionality is working. I'm not sure if there is a flaw with emails sent to @sent.com email addresses. Does anyone have any ideas?

1275935 - HEART OF CARY TOASTMASTERS
New members first name: Parth

I can see the email being accepted by your members email service, tell him to check his spam box.

Dec 27 01:47:02 toastmastersclubs sendmail[19717]: xBR1l1If019714: to=<parth.bakshi@sent.com>, ctladdr= (501/502), delay=00:00:01, xdelay=00:00:01, mailer=esmtp, pri=122198, relay=in1-smtp.messagingengine.com. [66.111.4.73], dsn=2.0.0, stat=Sent (Queued as E57E36144F2)
Dec 27 01:49:02 toastmastersclubs sendmail[20500]: xBR1n0kY020497: to=<parth.bakshi@sent.com>, ctladdr= (501/502), delay=00:00:02, xdelay=00:00:02, mailer=esmtp, pri=122198, relay=in1-smtp.messagingengine.com. [66.111.4.72], dsn=2.0.0, stat=Sent (Queued as ED7056DA2C8)

I sent a new one today and it went through as well
Jan 7 01:21:20 toastmastersclubs sendmail[10811]: 0071LITj010807: to=<parth.bakshi@sent.com>, ctladdr= (501/502), delay=00:00:02, xdelay=00:00:02, mailer=esmtp, pri=122197, relay=in1-smtp.messagingengine.com. [66.111.4.72], dsn=2.0.0, stat=Sent (Queued as BDA26726157)

Thank you for checking Brian. I'll ask him to check his spam folder again.