Cloudformation - yaml enviromental variables update - domain and cookie

I setup Retool on premise using cloud formation. Based on the other threads it states I need to define the environment variables for for HTTPS by 1) enabling cookies and 2) setting a base domain name.

I have read the retool-onpremise/retool.yaml at master · tryretool/retool-onpremise · GitHub file and tried to mirror it, but to no avail it keeps failing.

Preface - I'm not an SDE and have little experience. I'm using the cloud formation designer with YAML.