Error Private key doesn't match Certificate is thrown when you try to import public key:
There are two possible reasons for this issue:
1. The certificate is in PKCS7 format that is currently not supported by RAS;
2. The certificate doesn't match the CSR indeed.
1. Please make sure that the certificate is not in PKCS7 format;
2. Use https://www.sslshopper.com/certificate-key-matcher.html to check if the certificate matches the CSR actually. If it doesn't, the certificate is wrong: