A browser session can expire or be revoked. Clearing cookies, signing out, changing devices, or an account-access change can also end the session you were using. This is different from a WhatsApp number disconnecting.
Sign in again through the normal Console page and check the intended account and team. Do not paste a session token into a page or ticket to recover access. If sign-in repeatedly succeeds and immediately returns you to sign-in, report the browser, time, page address, and visible error. Mention recent cookie or privacy-setting changes so support can distinguish a browser issue from an account-access problem.