No connection between Macbook air 2017 and a TV

Need help to connect my Macbook air 2017 to a Toshiba Regza TV. Everything looks OK until I switch on the TV, a "No video signal" comes up and there is no connection. I connected through a minidisplay port to a HDMI port on the TV. Have also tried with another computer and there is nothing wrong with the cable.

Before I used a Macbook air 2013 and it worked fine. Any suggestions?