Apollo.io reports that effective cold emails should be personalized, relevant, and value-driven, aiming for quality responses ...

Learn how to password-protect or encrypt emails in Microsoft Outlook desktop client and Outlook on the Web. You can also read encrypted email outside Office clients.

Follow the prompted instructions and use a suitable suggestion to fix the problem. See if you can now add file attachments using drag and drop in Outlook. How do I change email attachment settings?