Office Online Server with SharePoint 2016 : ERROR

Hi All,

I have configured Office online Server  with SharePoint 2016. It was working fine. Yesterday my system gets shut down all of sudden due to some reason. When I tried to open office documents in our SharePoint Site in browser it gives below error.

I have checked http://servername/hosting/discovery also, its working fine. I am unable to fine the problem where it occurred all of sudden.

I am also not logged in Site with System Account.

Please help.