Works with Chrome, Firefox, and Edge on Windows 10, but not linux or Android

[sootsnoot]

By not working on Linux (Zorin linux) or Android, I mean that I can go to the site and the home page is displayed, with the regular WordPress login button in the upper left corner. The site seems to work normally, login is not forced. By works on my PC, I mean that if I go there when not logged in, the login page is displayed, and I can't get to any other page until I successfully login.

I don't understand how this is possible, since login state is managed by cookies in the browser, the browser should work the same in that regard on all platforms.

What can I do to help debug this? I don't want to post the URL here because there can be phone numbers and email addresses there. Is there an email address where I could send the site url privately?