Good evening, 

I've been trying to send test emails to test my campaign to a few emails. Every time, I got the message that the test campaign was sent successfully but no email is received at all. 

It's not even in the spam folder.

I tried to change the sender address to no avail, the problem remains the same. 

I also try to send a test email from a different campaign but again, with no success. It looks like all test emails just don't work.