Deleting emails in Outlook makes them no longer viewable in Zoho CRM

Deleting emails in Outlook makes them no longer viewable in Zoho CRM

When I delete an email in Outlook, it makes the email no longer viewable in the Contact record in ZohoCRM. I do not want to leave tons of emails in my Outlook inbox. How do I delete them without them being removed from my ZohoCRM contact record? I am using IMAP, in case that makes a difference.