The problem happened after I reboot my server by using:

sudo reboot

After I reconnect, I <cd> to the NodeBB dictionary:

cd /home/NodeBB

And then I input:

./nodebb start

And I see the log by typing

./nodebb log

I saw this:

I type

mongo

and I met this

I cannot start my server now ,it is 502

Who can help me solve it?
Thanks!

Returned this @julian

I have just searched the stackoverflow and tried all the ways.But it still doesnt work...

I am waiting for the cooldown...