Send email with mailx/msmtp only works for root user

I'm struggling to find a solution. I installed heirloom-mailx and msmtp following this site . I can send emails (using gmail) as root user. The problem is with non-root user: the messages go to a queue folder (/var/spool/mqueue) and never are sent. I have little experience with linux. Could you help me? System: Cubieboard 1 - Armbian Legacy Jessie server 3.4.112 .mailrc set sendmail="/usr/bin/msmtp" set message-sendmail-extra-arguments="-a gmail" ======================================================================================== .msmtprc #Gmail account defaults logfile ~/msmtp.log account gmail auth on host smtp.gmail.com from XXX@gmail.com auth on tls on # tls_trust_file /etc/ssl/cert.pem tls_trust_file /usr/share/ca-certificates/mozilla/Equifax_Secure_CA.crt user XXX@gmail.com password XXX port 587 account default : gmail ======================================================================================== /var/log/mail.info Oct 30 21:08:52 localhost sm-mta: u9U129DY004614: to=, ctladdr= (0/0), delay=22:06:43, xdelay=00:00:00, mailer=esmtp, pri=11910461, relay=alt4.gmail-smtp-in.l.google.com., dsn=4.0.0, stat=Deferred: Connection timed out with alt4.gmail-smtp-in.l.google.com. mail.log: Nov 1 20:08:27 localhost sendmail: uA1M8RXu015107: from=debian-transmission, size=380, class=0, nrcpts=1, msgid=, relay=debian-transmission@localhost Nov 1 20:08:27 localhost sm-mta: uA1M8RiY015111: from=, size=628, class=0, nrcpts=1, msgid=, proto=ESMTP, daemon=MTA-v4, relay=localhost [127.0.0.1] Nov 1 20:08:27 localhost sendmail: uA1M8RXu015107: to=XXX@gmail.com, ctladdr=debian-transmission (107/114), delay=00:00:00, xdelay=00:00:00, mailer=relay, pri=30380, relay=[127.0.0.1] [127.0.0.1], dsn=2.0.0, stat=Sent (uA1M8RiY015111 Message accepted for delivery) Nov 1 20:13:43 localhost sm-mta: uA1M8RiY015111: to=, ctladdr= (107/114), delay=00:05:16, xdelay=00:05:16, mailer=esmtp, pri=120628, relay=alt4.gmail-smtp-in.l.google.com. [74.125.130.27], dsn=4.0.0, stat=Deferred: Connection timed out with alt4.gmail-smtp-in.l.google.com. Debian-transmission is an user created by transmission. Transmission calls the bellow script after downloading: printf "The torrent $TR_TORRENT_NAME was downloaded successfully at $TR_TIME_LOCATIME" | /usr/bin/mailx -s "Transmission downloaded : $TR_TORRENT_NAME" XXX@gmail.com Maybe I could add the mailrc and msmtprc parameters to the script?