can’t access newly created Shift

after a fresh install, I created a few employee and shifts.
Shifts are showed on master calendar and “your schedule” page.

However, shifts cannot be reached as a post.
WP displays a page not found message

URL is with the scheme /shift/[shift-title]

Shift cannot be reached neither from “all shifts” admin backend neither from edit post form with “view shift” button nor from schedule pages

On the other hand a simple WP post can be accessed in a regular way

Any idea what’s wrong ?