I want to know why the delegation does not work with other staking pools

I started staking at Test Net Shelly a few days ago. There is no reward, so I want to delegate to another place, but it does not work.

you have to wait 2 or 3 days after you delegated your coins to an other pool before you get any rewards.

Even after 2-3 days, the epoch does not proceed, so compensation is not applied. So I tried to delegate to another staking pool, but I got a success message and the status changed from pending to -> failed…