Using New Outlook on Windows for personal email, calendar, and contact management
Hi there! I hope you are well.
About the draft that keeps appearing under Deleted Items even after you delete it and sign out, it may actually be stuck in Outlook's deleted/recoverable items.
Just to confirm, are you using the Outlook app to delete this email? If so, I'd suggest trying Outlook on the web if you are using a Microsoft email address and check Deleted Items > Recover items deleted from this folder. If you see the draft there, permanently delete it from that location as well. You can also try emptying the Deleted Items folder afterward.
You can access the Outlook web at https://outlook.live.com
If it continues to reappear, it may be getting recreated by another Outlook app or device that is still syncing your mailbox. In that case, checking the account on Outlook on the web can help determine whether the issue is with the mailbox itself or the Outlook app you're using. More details or reference can also be found on the Microsoft support website:
https://support.microsoft.com/nb-no/outlook/cannot-empty-the-deleted-items-folder-in-outlook-com