That is too much: you think you enjoy your Amazon AWS® EC2 instance that you are paying each hour?… You are not: Amazon AWS® refuses to open the port 25. Amazon AWS® was supposed to give productivity and time gains to its customers, now you are just wasting their time.
You cannot force your customers to use Amazon SES® to send out emails: your customers do not want that. Is it too much to ask? Okay, yes, it is.
Quantum Hosting® has decided to unwind all its servers with Amazon AWS® and to change provider. It will not refer any new customers to Amazon AWS® either starting today.