What happens to mail sent outoing limit exceeded?

What happens to mail sent outoing limit exceeded?

Our organization recently had an account blocked due to sending beyond our daily quota. I was able to sign in an unblock the account. However, I am assuming that any further email will not be sent until the next day. Are any emails delivered to the SMTP server being queued or are they being dropped? It's fine if they are queued and will go out later; if they are being silently dropped then this will be a huge problem.

Thank you.