Are you trying to in Microsoft 365, or are you troubleshooting attachment security on a local server? EnableDownloadDomains blocks picures in OWA
The most common use for a TXT file or record related to OWA is to prove you own the domain so you can use it for professional email. owa domain.txt
: Navigate to the Microsoft 365 Admin Center under Settings > Domains . Are you trying to in Microsoft 365, or