error 550 report continually pops up "some errors occured etc" can't stop it

[AWS]

On sending an email to a closed account, a pane opens that says, "some errors occurred etc" &amp gives me an error 550 message &amp says that the message couldn't be sent to that email address. I can't seem to stop the error message from poping up every time I have
an incoming or outgoing message.

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