Q:

SSL handshake problems with Qt 5.9 only when deployed in client

I have a desktop application built in Qt 5.9 using MinGw in Windows, it pulls data from a database and displays it in the GUI in a organized manner.  
Deploy of the project in release configuration is working fine in 4 different computers that i tested (windows 10 and windows 7)
But, in my client's computer, there are SSL handshake errors whenever a connection is tried.
Error that occurs is:
qml: Error during SSL handshake: error:1407742E:SSL routines:SSL23_GET_SERVER_HELLO:tlsv1 alert protocol version

Current solutions that i found here and tried:

Deploy openssl newest dlls in my release folder (alongside qt's dlls)
Implement ignoreSslErros(), as in the code bellow: 
QObject::connect(_socket, SIGNAL(sslErrors(QList<QSslError>)), _socket,SLOT(ignoreSslErrors()));

Where the signal and slot used are defined in QWebSocket's documentation.
SLOT: http://doc.qt.io/qt-5/qwebsocket.html#ignoreSslErrors
SIGNAL: http://doc.qt.io/qt-5/qwebsocket.html#sslErrors
This implementation didn't work.
I got to the point of remote accessing my client's computer and running Qt in debug configuration, and the only thing i got was these build warnings that dont occur when i build on my computer:
qt.network.ssl: QSslSocket: cannot resolve TLSv1_1_client_method
qt.network.ssl: QSslSocket: cannot resolve TLSv1_2_client_method
qt.network.ssl: QSslSocket: cannot resolve TLSv1_1_server_method
qt.network.ssl: QSslSocket: cannot resolve TLSv1_2_server_method
qt.network.ssl: QSslSocket: cannot resolve SSL_select_next_proto
qt.network.ssl: QSslSocket: cannot resolve SSL_CTX_set_next_proto_select_cb
qt.network.ssl: QSslSocket: cannot resolve SSL_get0_next_proto_negotiated
qt.network.ssl: QSslSocket: cannot resolve SSL_set_alpn_protos
qt.network.ssl: QSslSocket: cannot resolve SSL_CTX_set_alpn_select_cb
qt.network.ssl: QSslSocket: cannot resolve SSL_get0_alpn_selected

A:

Given the warnings I would suggest that the OpenSSL library at the clients computer does not support TLS 1.1+ but that the server requires it. And while you might have attempted to provide the new SSL libraries these messages show that your program does not use these new libraries.

