> A message that you sent could not be delivered to one or more of its > recipients. This is a permanent error. The following address(es) failed: > > packa...@groonga.org > host aspmx.l.google.com [2a00:1450:400c:c0c::1a] > SMTP error from remote mail server after RCPT TO:<packa...@groonga.org>: > 550-5.1.1 The email account that you tried to reach does not exist. > Please try > 550-5.1.1 double-checking the recipient's email address for typos or > 550-5.1.1 unnecessary spaces. Learn more at > 550 5.1.1 https://support.google.com/mail/?p=NoSuchUser > p16si1506256wre.147 - gsmtp
This is caused by recent mail service migration for groonga.org. The issue has fixed now.