Suddenly order emails not received

[isaacr25]

I have a store that's been up and running for over 3 years now. I have not made any major changes in quite some time.

Something strange started happening yesterday. Normally I receive an order email from the store along with a receipt email from authorize.net. Now, I get the order emails intermittently. Some come through, some don't. So I'm receiving receipt emails for which I have no order emails.

Any thoughts on why this may be happening, and how I can troubleshoot? Thanks guys.

[Kim]

First, ask your host if they have changed anything. Second, check to make sure you haven't been hacked.

[isaacr25]

How do I check to see if I've been hacked?!