It's really just what the site says:

"For permits beginning on 07/29/2025, check back on 07/15/2025 at 7:00 AM PDT."

There must not be any permits available and the walk up permits are released 2 weeks before at 7am PDT.

You can keep looking until then, since sometimes people cancel permits.

Also be open to other entry points. Cottonwood Pass is VERY much sought after and may be hard to get, but Trail Pass is non quota. Might add at least a day to your trip, though.