Cannot post to !travel@notdigg.com

Searching mags for “travel” then browsing the list of results is apparently the only UI-supported way to reach a mag. When !travel@notdigg.com did not appear in the list, I manually tried to visit https://fedia.io/m/travel@notdigg.com directly. It gives a 404 error. How can this be overcome?

Same problem for !travel@hilariouschaos.com