Outlook Mails will be deleted after i upload the Mail into ERPnext

Hello Everyone,

we are a company of Germany. We use ERPnext since the 1. January 2021.

We have a problem with uploading Mails from Outlook in ERPnext.
When i upload an Email from Outlook in ERPnext with drag and drop, the Email will be deleted from outlook. It seems that is a problem from ERPnext.
When i upload an Mail from Outlook in for example Gmail the Mail will not deleted from Outlook.

Can someone help me in this problem?

Best greetings from Germany
Artur Eckstädt