Usually, this situation occurs if a 3rd party program interacts with the auto-reply email, before Auto Reply Manager is able to send it. Most of the times, the cause is related to an anti-virus program that is configured to check emails and to prevent "viruses" to send emails on your behalf, just like Auto Reply Manager does automatically.
So I would suggest disabling or re-configuring your anti-virus in order to avoid scanning outgoing emails.
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DS Development
Outlook Add-ins and Outlook Productivity Solutions
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