My outlook.com email won’t receive emails, but can send them. Help anyone?

I set my emails to come through Outlook.com, and I created a "send/receive" type of account. But now, for some reason, it will no longer receive any emails, however, I can still send emails from this acc. I've tested it several times and for whatever reason it won't receive emails. This is bad, I run and independent business, and rely on this email for customers and other business associates. PLEASE HELP!!