Modify sample accept.cnf

# Example configuration file

# Connects to the default port of s_server

Port = localhost:4433

# Port to listen on

Port = 4433

# Disable TLS v1.2 for test.

# Protocol = ALL, -TLSv1.2

# Only support 3 curves

Curves = P-521:P-384:P-256

# Automatic curve selection

ECDHParameters = Automatic

# Restricted signature algorithms

SignatureAlgorithms = RSA+SHA512:ECDSA+SHA512