admin-url-cookie-path

Cookie path must match

Since Strapi 5.51, the admin authentication cookie path defaults to /admin regardless of url. When you change url, also set auth.cookie.path to the same value. Otherwise the admin panel cannot read its own authentication cookie: the login request succeeds, every request after it is rejected, and the panel returns to the login page with no error.

/config/admin.js

module.exports = ({ env }) => ({
  url: "/dashboard",
  auth: {
    cookie: {
      path: "/dashboard", // must match url
    },
  },
});

After changing auth.cookie.path, rebuild the admin panel before starting Strapi, as this value is inlined into the admin bundle at build time.