API web source credential has a SSL/TLS error

I try to connect Vmware vSphere Client web page from Power BI using web source.

I have my credential and it works on browser.

I get the error:

Details: "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel."

I tried 

Clear the Secure Sockets Layer (SSL) state. To do this, follow these steps:

1. In Internet Explorer, click Tools, and then click Internet Options.
2. Click the Content tab, and then click Clear SSL state.

But it doesn't work.

My questions:

1. Any other way can solve this problem?

2. Is it possible to link any webpage through the PBI web source as long as I have an account and password for the webpage?