Copilot button in Outlook 365 App

There is a documented missing-Copilot-button issue in classic Outlook, but first confirm whether that is the application you use. Microsoft's advisory describes missing navigation and ribbon entry points after build 20026.20182 or later and lists the issue as under investigation. It does not establish that every missing button on a personal subscription has that cause. Record your Outlook version, build, and the account whose mailbox you are viewing, then give those details to the support team handling your case. If your configuration matches the advisory, Microsoft's workaround is new Outlook or Outlook on the web; repeated profile creation and cache clearing have not consistently restored the button. If your configuration differs, check your subscription entitlement and use Update License in a Microsoft 365 desktop app, then restart the apps. Do not buy another plan to troubleshoot this, and do not assume a fix date that Microsoft has not published.