I Can't MLLearn with Standalone build (mlagents-learn with --env with --num-envs={n} )

[changdoc]

I found below article’s comment
backend must be mono… not il2cpp

Couldn't connect to trainer on port 5004 using API version 1.5.0. Will perform inference instead.

One thing I found, that could help others: ML Training in build won’t work if you try to use IL2CPP compiler. So, make sure your project is set to Mono.

when I changed backend il2cpp to mono. It’s doing well!