I have postfix and dovecot installed on Debian. I have my droplet named as an FQDN (mxwsrv1.cbuchanon.org). I have an A record for mail.cbuchanon.org pointing to the IP of my droplet. I have an MX record pointing cbuchanon.org to mail.cbuchanon.org. The host name on the server shows as mxwsrv1.

Initially, I had the port blocked and could see Google trying to connect when I sent e-mails through gmail. I opened the port and that cleared the error. I've checked that mail.cbuchanon.org points back to my server IP and am coming up empty as to how else I could trace where the issue is occurring. Any guidance would be greatly appreciated.

aliasmaps = hash:/etc/aliases
aliasdatabase = hash:/etc/aliases
appenddotmydomain = no
biff = no

brokensaslauth_clients = yes

myorigin = /etc/mailname

inetinterfaces = all
mailboxcommand = /usr/lib/dovecot/deliver -c
/etc/dovecot/conf.d/01-mail-stack-delivery.conf -m "${EXTENSION}"
mailboxsizelimit = 0
myorigin = /etc/mailname
readmedirectory = no
recipientdelimiter = +
relayhost =
smtptlssessioncachedatabase = btree:${datadirectory}/smtpscache
smtpdsaslauthenable = yes
smtpdsaslauthenticatedheader = yes
smtpdsaslpath = private/dovecot-auth
smtpdsaslsecurityoptions = noanonymous
smtpdsasllocaldomain = $myhostname
smtpdsasltype = dovecot
smtpdtlsauthonly = yes
smtpdtlsreceivedheader = yes
smtpdtlssessioncachedatabase = btree:${datadirectory}/smtpdscache
tlsrandomsource = dev:/dev/urandom

myhostname = mxwsrv1.cbuchanon.org

myhostname = mail.cbuchanon.org

mydestination = $myhostname, cbuchanon.org, mxwsrv1.cbuchanon.org, localhost.cbuchanon.org, localhost

mydestination = localhost, mail.cbuchanon.org, localhost.cbuchanon.org
mynetworks = 127.0.0.0/8 [::ffff:127.0.0.0]/104 [::1]/128
mydomain=cbuchanon.org

smtpdbanner = $myhostname ESMTP
smtpdhelorequired = yes
smtpdhelorestrictions = permitmynetworks,
rejectnonfqdnhelohostname, rejectinvalidhelohostname,
rejectunknownhelohostname, permit
smtpdrecipientrestrictions = rejectunknownclienthostname,
rejectunknownsenderdomain, rejectunknownrecipientdomain,
rejectunauthpipelining, permitmynetworks,
permitsaslauthenticated, rejectunauthdestination,
rejectinvalidhostname, rejectnonfqdnsender
smtpdsenderrestrictions = rejectunknownsenderdomain,
rejectsenderloginmismatch
smtpdsenderloginmaps = $virtualmailboxmaps

unknownaddressrejectcode = 550
unknownhostnamerejectcode = 550
unknownclientreject_code = 550