LC_E_VALIDATION_CERT_NO_KEYEXCHANGE error on Skype for Business

To fix the error (see below) with a certificate you need to recode pfx with SFB accepted CSP "Microsoft RSA SChannel Cryptographic Provider" , as explained here:

https://www.componentspace.com/Forums/PrintTopic1578.aspx 

openssl pkcs12 -in idp.pfx -out idp.pem

openssl pkcs12 -export -in idp.pem -out new-idp.pfx -CSP "Microsoft Enhanced RSA and AES Cryptographic Provider"

Log Name:      Lync Server

Source:        LS Protocol Stack

Date:          1/25/2022 9:35:40 AM

Event ID:      14397

Task Category: (1001)

Level:         Warning

Keywords:      Classic

User:          N/A

Computer:      

Description:

A configured certificate could not be loaded from store. The serial number is attached for reference.

Extended Error Code: 0xC3FC7D95(LC_E_VALIDATION_CERT_NO_KEYEXCHANGE).