Hi, csat!
I tried to duplicate the situation you're having, and found this out:
Under the Sending Email tab, in Security when "Use Secure Connection" option has "SSL Encryption" or "TLS Encryption" in it, sending hangs at the queue as you have described, and ultimately fails. Now, make sure that this option has "No encryption" in it.
If this doesn't solve it, just go ask again and I'll be happy to help out.
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