I have a MacBook Air , 2 external monitors no signal to one of the monitors

That's what is supposed to happen. The M1 Mac notebooks (Air and Pro) support only one external display – resolution up to 6K, but only one.

Simultaneously supports full native resolution on the built-in display at millions of colors and:

• One external display with up to 6K resolution at 60Hz

From MacBook Air - Technical Specifications - Apple.

If your MacBook Air is from 2017 or before, or is one of the new M1 MacBook Airs, it only supports a single external display. Only the 2018, 2019 and 2020 Intel MacBook Air models support two external displays.

I have an M1 Macbook Air. Connecting both into the USB-C drives and only one works. But what is weird is the other one is putting out sound when on Zoom calls. I have the LG 4K screens that I bought for my 2018 Macbook Pro and they worked great. Now I went over the M1 Air and only one works. I have done all the trouble shooting if I plug one in it works on the A screen, if I plug another one in it works on the B screen but not A. Tried detect displays, rebooting, plugging in and out and nothing works.

When both are plugged in only one works.