Welcome @JulienBot. Thanks for joining the Community!  

You could use the Schedule by Zapier app to trigger at a specific time of day. See our Schedule Zaps to run at specific intervals guide for more details. As for checking whether an email was received during a specific time, that would depend on the email app you’re using. 

I know that the Gmail app for example has a Find Email action which allows you to search within a specific time frame when using after: and before: in a search query. You can find out more details here: Search operators you can use with Gmail.

You would then want to follow that up with a Filter by Zapier action to only allow the Zap to continue if no email was found by the Find Email action. The Find Email action will return a _zap_search_was_found_status field that contains a value of false if nothing is found. You can find out more about how to set up filters here: Add conditions to Zaps with filters.

If you’re not using Gmail then it might not be possible to narrow the app’s search action to look for an email within a specific time frame. Can you confirm what email app you’re using? It may be that you’d need to create a workaround of adding a record of each email that is received along with the time and adding it into a third party app like Google Sheets or Airtable for example. Then you could potentially search that third party app to see if any emails were received.

I do also want to note that adding search and filter actions to a Zap would make it a Multi-Step Zap which isn’t available on the Zapier Free plan. Making a paid Zapier plan required for this kind of workflow.

Hope the above is helpful. If I’ve misunderstood what you’re looking to do here or you run into any issues on giving the above suggestions a try just let us know!