Error in accessing Kibana

Hi All

Am migrating from 6.4.3 to 6.7.1
ES installation is fine but the kibana 6.7.1 fails. Upon accessing the application, am getting
" Kibana did not load properly. Check the server output for more information." with the information "vendors.bundle.dll.js Failed to load resource: net::ERR_CONNECTION_RESET" in the console.

Could someone help on this?
I have attached the error

What does the kibana server output say?

Actually it works. The issue occurred while accessing the server through VPN.
Let me check.

Thanks for the reply.