Emails sent via Outlook to Contacts create new leads?

Emails sent via Outlook to Contacts create new leads?

I have set-up Zoho CRM Outlook integration to create a lead if the recipients address aren't found in Contacts or Leads.

Now I've sent emails to multiple contacts and for all of them Zoho CRM created new leads, although all email,addresses existed as primary email in Contacts.

What is wrong?

Thank you for help.