Confluence installed on Ubuntu after 2 days running, confluence cannot be connected anymore.

[Londa Liau]

Confluence version: 6.4.1

Confluence license: 10 persons with 1 year maintenance 

Ubuntu version: 16.04LTS

External database: No, use built-in data base 

Issue description: 

I cannot connect to confluence server anymore even I reboot ubuntu for couple times.

Any idea to make my confluence come back?

Thank you.

Londa

[Londa Liau]

The confluence server is still down even I performs "sudo ./etc/init.d/confluence restart" or reboot ubuntu.