Install Central on Ubuntu 20.4 on AWS EC2 instance

In your ~/central folder, run docker-compose logs service and docker-compose logs mail and see what it says.

My guess is that either you didn't get the formatting right in the JSON file or the credentials themselves are incorrect. It should like something like this.

"email": {
 "serviceAccount": "no-reply@${DOMAIN}",
 "transport": "smtp",
 "transportOpts": {
   "host": "email-smtp.us-west-2.amazonaws.com",
   "port": 587,
   "auth": {
     "user": "ANVGGCSWYFTQYPDLEH2Q56S7U3G8A5",
     "pass": "0IFIVZ4CUnU2klftRzroL8OLUCxBt8anVGanVGGCSWyft"
   }
 }