Might be an issue with Outlook sync? You can write code to sync the folder but then you'll have to add static wait for it's completion.
Another approach based on my understanding of your issue, I would suggest you take earliest time from last item processed so that you don't miss on anything even if the email is not processed in current run it will get processed in next.
@Zdeněk Kabátek I think giving now() as latest wont work because it's just earliest=<recievedtime
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Gopal Bhaire
Analyst
Accenture
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