I am trying to connect my MS-excel to postgresql 9.6

Firstly, It gave me error that it does not have the required library. So I downloaded ngpsql.

After that, it gave me error that it cannot accept the server certificate.

DataSource.Error: TlsClientStream.ClientAlertException:      CertificateUnknown: Server certificate was not accepted. Chain status: A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider. 

So, I performed the following steps.

1 – Got the postgres server certificate (/etc/ssl/certs/ssl-cert-snakeoil.pem) and converted it into .crt file.

2 – copied it to my windows and installed the certificate on my windows using this page

http://www.cs.virginia.edu/~gsw2c/GridToolsDir/Documentation/ImportTrustedCertificates.htm

3 – It says import was successful.

But still I keep getting the same error. It says that the server name is not mentioned in the certificate.

How to make a correct server certificate?