Getting "no video signal" when I hooked up my 2018 Sony DVD player to my 2011 Toshiba flat screen tv.

More information needed:

What ports did you use?

What cables did you use?

Have you tried another known working cable(s)?

Does the TV (same port) work with other DVD players?

Does the Sony DVD player work with other TVs?

Also double check the applicable menu settings on the TV. All too easy to forget to select the video input port being used for DVD input....