Sending Test Emails

It has happened to me a number of times when working with different clients. Sometimes there is a backup/delay with the system. How long have you been waiting? If it continues to happen you can always contact support for them to look into the issue.
 

As always, check your Spam/Junk folders to make sure they aren't there :)

I have been waiting hours. They are not in my spam/junk folders. I was receiving them all day yesterday and starting last night, nothing.

Are you sending them from the email asset ("send sample") or do you have a specific smart campaign defined that runs these tests?  If the latter, perhaps you've exceeded the number of times you can run through the flow.

This happened to us last year.  What ended up solving this was to white list the IP addresses that Marketo uses to send the tests.  Here is the article we used: https://app-aba.marketo.com/guide/displaySuccessContent?startURL=%2FMarketoArticle%3Fid%3DkA050000000KypE

Also, this Discussion thread helped as well for more trouble shooting: https://community.marketo.com/MarketoDiscussionDetail?id=90650000000PDV8AAO

I have been using the "00 Send Yourself Test Emails". I looked into if I exceeded the number of times I can run through the flow and it seems to be that I don't have a limit. I can test each email individually but, not the entire flow.