[stunnel-users] Stunnel's Windows client stopped working in Iran

I have a Stunnel server that users connect to from Iran, to circumvent internet censorship. It was working for years but in recent days Stunnel's Windows client has stopped working (maybe due to censorship), but the Android clients like (SSLSocks and SSL Encryptor) do work. So do you have any idea what would be the difference between Windows and Android clients which can help me fix the problem? Any help appreciated.