SSRS 2008- Underlying connection was closed – could not establish trust relationship for SSL/TLS

This error comes, when I tried to access the report manager at http://localhost/Reports_SQL

Open Reporting Services Configuration Manager - Click on Report Manager URL section. It shows

Here https:// has been configured. But I did not do it. May be, the default configuration. I clicked on Advanced. See the screenshot below:

The default SSL certificate for both IPv4 & IPv6 was configured which was causing the problem. This default configuration was done by SSRS 2008 installation. Now, I removed both the configurations and clicked OK. But it still not done. The same configuration has to be removed from “Web Service URL” section in SSRS configuration – exactly in the same way.