How to solve:
1. First check is internet is allowed for that OLT by pinging 1.1.1.1 or 8.8.8.8 from Diagnose. If not getting ping, that means internet isn't allow for the OLT, then tell the network admin from allowing the internet for the OLT.
2. If getting ping on 1.1.1.1 or 8.8.8.8 then but not getting ping on ems.tnrsoft.com then check the DNS is setted or not in OLT. If not then set DNS to 1.1.1.1 and 8.8.8.8
3. If still not connecting that means that means that OLT can't connect with domain then change domain ems.tnrsoft.com to 160.187.130.54 this IP.