Can't send After Effects composition to Media Encoder...
Seems like this is a bug. Sending a comp to media encoder queue from AE doesn't work. ME starts, but the queue remains empty. I also can't import an AE comp from inside ME itself. After Effects version 17.0.6, Media Encoder 14.1
Antoine Autokroma commented
You could try to encode directly from AEfx : https://www.autokroma.com/AfterCodecs/After_Effects