what should the settings be on my mac mini for the mac mail program?

For some reason my mail program on my mac mini will no longer receive or send email from my iCloud account. I am on vacation in Florida and my provider down here is comcast. I have spent much time trying to figure out what must have happened - everything was working fine at home!! I have talked to comcast twice but I am still having problems. The only email I can receive and send is through our email at comcast.net. Can someone please tell me what my iCloud settings on my computer should be - I am afraid I have altered something that is creating the problem, as I am able to connect to the internet o.k. Any suggestions?

Thanks.