TLS_SecurityLevel is an integer parameter that sets the SSL library security level for the enclosing clause. Security levels were added in OpenSSL 1.1.0 and are detailed in OpenSSL manual page SSL_CTX_set_security_level. There is no default and the system default is used. This parameter may be needed if you see unexpected TLS errors with older TLS peers.

Security level can also set together with ciphers in which case TLS_SecurityLevel is not needed. For more information, see Section 3.11.9. TLS_Ciphers

# The default pn this system, 2, is too strict for our peers,
# lower it for this Radiator module
TLS_SecurityLevel 1