This question already has an answer here:
What is the best Stack Exchange site to get feedback on e-mail hosting? In a nutshell, I'm trying to get some feedback on affordable email hosting providers to host 18,000+ e-mail accounts with some usage specifics. I tried asking this question on the Webmasters Stack Exchange as suggested in this meta post: Where should I ask a question about email however my question was put on hold because it apparently appears to be off-topic.
Which Stack Exchange site can I ask this question on?
Note: I have specific requirements and am looking for an objective list of email hosting providers that meet these requirements, so this is not a subjective question.