email error

Got this email. I know the email for Justin is correct - he works for me and that is his email.

justinnegron@isearch.co.jp appears to be an invalid or non-working recipient email address. (One Advertised SMTP server permanently refused mail.)

*** Please check the email address to make sure it is not misspelled. ***

If you believe this warning is incorrect, please visit support.toastmastersclubs.org and post a support request message.

Thanks,
Joe Peters
VPE, Tokyo American Club TM

I can see Justin email receiving mail.
Make sure he has white listed agenda@toastmastersclubs.org, and server@toastmastersclubs.org

Oct 11 06:01:54 toastmastersclubs sendmail[7022]: 09B61ITD006886: to=<justinnegron@isearch.co.jp>, ctladdr= (501/502), delay=00:00:03, xdelay=00:00:03, mailer=esmtp, pri=4939122, relay=mx10.mailspamprotection.com. [146.66.121.211], dsn=2.0.0, stat=Sent (OK id=1kRUQa-000936-Qb)
Oct 12 05:28:22 toastmastersclubs sendmail[10672]: 09C5SH3H010647: to=<justinnegron@isearch.co.jp>, ctladdr= (501/502), delay=00:00:02, xdelay=00:00:02, mailer=esmtp, pri=304807, relay=mx10.mailspamprotection.com. [146.66.121.215], dsn=2.0.0, stat=Sent (OK id=1kRqNh-000Bns-So)

Thank you. Justin changed his email to his GMail account so no issue now.

Regards,
Joe