I am trying to connect my 8 gen IPad to a tv(not smart) via a lightning cable. It isn’t working. Any suggestions?

You have referenced three separate devices; an older iPad running iOS 9, an iPad 8th gen running an unknown iOS or iPadOS version, and an iPhone 7 running an unknown iOS version.

Usual path for connecting from a device with a Lightning connector to a TV is via a Lightning to HDMI adapter, and an HDMI cable. Apple offers one of these HDMI adapters, as do other vendors.

Lightning Digital AV Adapter - Lightning to HDMI - Apple

If this is what you are doing, which adapter, which device, and whst have you already tried?

Try a different cable, as that’s probably the cheapest part to swap next.

The cable probably isn’t bad, but it does happen.

Alternatively, test this HDMI cable with a different HDMI source.

Also check with RAVIAD support.

Then try Apple digital AV adapter.

If you trying to play protected media content, the TV must support HDCP content protection.