Hashed mailing URLs do not work with view mailing links
CiviMail has a setting for 'Hashed Mailing URL's'
However, if this setting is enabled it is impossible to view the mailing.
Clicking 'View complete mailing' results in a server error:
We are working on a fix for this.
Possibly related to #911 ?
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information