I had this happen and the asterisk service was running, but the web interface couldn't seem to detect it. Running fwconsole restart would not complete, and it would get stuck "starting asterisk...." for a long amount of time.
In order to get fwconsole restart to work, we first had to kill the rogue asterisk service process.
Issue command: top
Find the process id of the asterisk process
Kill that process using the command: kill [processid] (enter the process id from the previous step)
The issue the normal command: fwconsole restart
This should then work, now that you've killed off the rogue asterisk process.