title: Can't login to backend after fresh install of the latest TYPO3 9.5 LTS
body: <p>Fresh install of TYPO3 9.5 LTS on Ubuntu 18 host. Went smoothly, new database, everything. Made up the backend user/password &amp; when finished, I was sent to the backend to log in.</p>
  <p>The login page seemingly just refreshes. If I use the wrong credentials it tells me they are wrong as it should. Going to sys_log I see &quot;user logged in from x.x.x.x&quot; but I'm not allowed further.</p>
  <p>The redirects actually sent to the server are:</p>
  <pre><code>303 POST /typo3?loginProvider=....
  303 GET index.php?route=/main&amp;token=...
  200 GET /typo3/ (returns the login page)
  </code></pre>
  <p>Any ideas on what to check appreciated: I know my way around servers but I'm new to TYPO3.</p>