Couldn't see the logs after deployment


After deployed meteor app with mup, I tried mup logs -f --tail=50 but all I got is:
[Server_IP]=> Starting meteor app on port:80

Even while I was running on that command, then accessed to my app, there’s no new log too.

And btw, how can I view all the logs? And is there anyway to manage logs conveniently?

And. below is /var/log on my server:

ls -a /var/log
.                 auth.log.1     ethcon.log     kern.log    ntpstats                 popularity-contest.4.gz  syslog       syslog.5.gz
..                bootstrap.log  faillog        kern.log.1  popularity-contest.0     popularity-contest.5.gz  syslog.1     unattended-upgrades
alternatives.log  btmp           fsck           lastlog     popularity-contest.1.gz  popularity-contest.6.gz  syslog.2.gz  wtmp
apt               dist-upgrade   imageboot.log  lxc         popularity-contest.2.gz   syslog.3.gz
auth.log          dpkg.log       installer      lxd         popularity-contest.3.gz  secure                   syslog.4.gz

I have the same question.
Where’s the mup logs file located?
How can I get the previous deployment log?

I think MUP uses docker to attach the STDOUT to some Logfile. Maybe there is something to find in the Meteor docker Image?