Hi @adriadrop,
Welcome to the community 
A key point to note is that in a testing environment an ERC777 token requires deploying an ERC1820 registry
_From: https://forum.openzeppelin.com/t/simple-erc777-token-example/746_
The issue is that the JavaScript VM doesn't have the ERC1820 registry deployed.
You would need to deploy the ERC1820 registry first if deploying to a JavaScript VM (I don't know how to do this in Remix without looking into it).
You could deploy locally to ganache-cli and deploy the ERC1820 registry using a script.
See the following example of a script to deploy ERC1820: How to deploy ERC777 using OpenZeppelin CLI? - #4 by abcoathup
Alternatively, you can deploy using Remix to a public testnet. I reproduced the error that you saw with a JavaScript VM and then deployed GLDToken to a public testnet. (Kovan)
