Fail to access to my private space when logged in on MacOS

I set up a private space for myself and use it as expected for about four months. But recently I changed to macbook pro and I always found the 404 error.
Firstly it comes as " Private spaces may not currently work in Safari or iOS. On MacOS, we suggest switching to another browser temporarily for this Space."

So I changed to Google Chrome. But It still works like " 404. Sorry, we can’t find the page you are looking for."

And it’s not in the incognito window. I changed the third-party cookies but nothing happened. Now I have to set the space to public when I’m using and set it to private immediately after I finish using. I’m very confused about it but when I googled I didn’t see similar cases. I’d really appreciate it if anyone could offer me some help.