Can't start Mattermost with systemctl

Hi, @emilushi

I compared the standard content of the mattermost.service with yours and the significant difference that I can see here is this:

EnvironmentFile=/etc/mattermost/mmomni.mattermost.env

Can I please confirm if the issue persists if you just use the standard mattermost.service below?

[Unit]
Description=Mattermost
After=network.target
After=postgresql.service
BindsTo=postgresql.service

[Service]
Type=notify
ExecStart=/opt/mattermost/bin/mattermost
TimeoutStartSec=3600
Restart=always
RestartSec=10
WorkingDirectory=/opt/mattermost
User=mattermost
Group=mattermost
LimitNOFILE=49152

[Install]
WantedBy=postgresql.service

Since you mentioned that sudo -u mattermost ./bin/mattermost works, let us look at this avenue first.