Can't Save a Portal Experience when using Custom Map

I am in the process of creating a custom map, and I want to test is out to see how it works so far. Unfortunately, when I try to save it online I simply get this message after waiting for a minute or so "Unable to create Experience. gRPC message exceeds maximum size 4194304: 172015191" 

No idea how to solve the issue from this awful error messsage.