Fwd: 553 ORCPT address syntax error on OpenBSD 6.7

[Larkin Nickle]

Someone from a corporation that uses GroupWise for email is unable to 
get their mail to deliver to my server running OpenBSD. In the log, I see:

Jul 27 22:10:39 hostname smtpd[34369]: de587a23456fe10c smtp 
failed-command command="RCPT TO:<m...@l......org> 
ORCPT=rfc822;groupwise...@l......org:1:1" result="553 ORCPT address 
syntax error"

My best guess is that GroupWise is maybe appending :1:1 to the end of 
the address and this is what is tripping this syntax error. They are 
able to successfully send mail to me on Google Mail, Outlook, etc. mail 
accounts.