Failed to load resource: net::ERR_CONNECTION_RESET

I am trying to call API, web site is served from IIS. But I get

Failed to load resource: net::ERR_CONNECTION_RESET

I tried, 1.checking the ssl certificate for this website, I see certificate hasn't expired 2.deleted all the cookies and loaded chrome

Still the issue persist, tried with mozilla. I see same issue

Note:I am able to access this website locally in the server. It doesn't show this error