Unable to view completed mailing if mailing hash enabled
- go to CiviMail > CiviMail Component Settings
- select option for Hashed Mailing URL's
- create and send a mailing
- go to a contact who has received the mailing, click the Mailings tab, and View the mailing
The preview is handled through the API and expects the Mailing ID to be the actual mailing table ID. If hashed ID's is enabled, it fails the variable type validation check.
To upload designs, you'll need to enable LFS. More information