Arduino to Arduino i2c not visible, but visible sensors LCD etc

Hi everyone.

I'm able to get my i2c scanner to pick up sensors and screens, but not other Arduino. Mainly Uno to Uno. I feel like I'm missing something obvious here, followed guides online but still not having any success.

Any advice please :slight_smile:

Can you show the sketch of the Slave ?
Did you connect both GND ?

Post a schematic not a frizzy thing, that will help us resolve your problem. Show all hardware and post links to technical information on them.