TL;DR: Server-side QSslSocket with protocol set to QSsl::TlsV1_0OrLater failes with handshake while with QSsl::TlsV1_2 works correctly. This issue seems to be macOS only.

I have QSslSocket based HTTPS Web server, where every incomming connection is wrapped into QSslSocket like this:

    QSslSocket *socket = new QSslSocket;
    socket->setProtocol(QSsl::SecureTlsV1_2);
    ...

    if (!socket->setSocketDescriptor(socketDescriptor)) {
        ...
    }


    socket->startServerEncryption();

When I access this server with curl, everythings works correctly. If I change socket protocol to QSsl::TlsV1_0OrLater, the SSL handshake fails emitting error signal with  SslHandshakeFailedError

Placing breakpoint at QSslSocketBackendPrivate::startHandshake() and doing small debug round-trip I can see that bool QSslSocketBackendPrivate::verifySessionProtocol() const returns false as it imho doesn't handle the QSsl::TlsV*OrLater variants of protocol enum correctly.