I'm not sure @mg2017. Usually I have more trouble with sifting through all the emails workflows send me in SB. I'd turn on logging and see if there is an error happening when it's trying to send the email. Or look at the transaction (if that's where you're trying to send from) on the Communication tab to see if it went. Other option if you might have them turned off. In production, go to Setup>Company>Email Preferences. There's a Sandbox and Release Preview subtab. There's an option there to have the Sandbox send no emails. Maybe you have it set that way?