Send mail with mailx only works for root user

Hi,

I'm struggling to find a solution. I installed heirloom-mailx following this site https://ubuntuforums.org/showthread.php?t=1711217. I can send emails (using gmail) as root user. The problem is with non-root user: the messages go to a query 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[4429]: u9U129DY004614: to=<XXX@gmail.com>, ctladdr=<root@localhost> (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.