Contao Frontend: Redirection failure after upgrade from 4.9 to 4.13

[Ruppel]

Hi,

I'm testing the upgrade from 4.9 to 4.13.
I managed to set the correct versions to all my extensions. See composer.json in the attachment.

But the frontend doesn't show up. It gives a "Umleitungsfehler" or "Too many redirections".
And sometimes appears an error in the backend at the bottom of the page., see screenshot.

Years ago I bought the theme "Big Company" from themes.contao.org. It seems, that this one unfortunately isn't being updated...
Perhaps there might be the problem, but I don't know where to start the search.

Any hints? Thanks in advance!

Best regards,
Markus

Log file, when trying to access the frontend:

[2024-01-04T10:06:48.308402+01:00] security.INFO: Populated the TokenStorage with an anonymous Token. [] []
[2024-01-04T10:06:48.366097+01:00] app.ERROR: RuntimeException: Failed to start the session because headers have already been sent by "/home/www/contao-4.13/vendor/symfony/http-foundation/Response.php" at line 381. in /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php:145 Stack trace: #0 /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php(352): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->start() #1 /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Session.php(261): Symfony\Component\HttpFoundation\Session\Storage\NativeSessionStorage->getBag('flashes') #2 /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Session.php(273): Symfony\Component\HttpFoundation\Session\Session->getBag('flashes') #3 /home/www/contao-4.13/vendor/contao/core-bundle/src/Resources/contao/library/Contao/Message.php(104): Symfony\Component\HttpFoundation\Session\Session->getFlashBag() #4 /home/www/contao-4.13/vendor/contao/core-bundle/src/Resources/contao/library/Contao/Message.php(36): Contao\Message::add('Facebook is cur...', 'TL_ERROR', 'FE') #5 /home/www/contao-4.13/vendor/pdir/social-feed-bundle/src/Importer/Importer.php(50): Contao\Message::addError('Facebook is cur...') #6 /home/www/contao-4.13/vendor/pdir/social-feed-bundle/src/EventListener/CronListener.php(88): Pdir\SocialFeedBundle\Importer\Importer->getInstagramPosts(NULL, 1, 20) #7 /home/www/contao-4.13/vendor/contao/core-bundle/src/Cron/LegacyCron.php(87): Pdir\SocialFeedBundle\EventListener\CronListener->getInstagramPosts() #8 /home/www/contao-4.13/vendor/contao/core-bundle/src/Cron/LegacyCron.php(33): Contao\CoreBundle\Cron\LegacyCron->runLegacyCrons('minutely') #9 /home/www/contao-4.13/vendor/contao/core-bundle/src/Cron/CronJob.php(44): Contao\CoreBundle\Cron\LegacyCron->onMinutely('web') #10 /home/www/contao-4.13/vendor/contao/core-bundle/src/Cron/Cron.php(131): Contao\CoreBundle\Cron\CronJob->__invoke('web') #11 /home/www/contao-4.13/vendor/contao/core-bundle/src/EventListener/CommandSchedulerListener.php(47): Contao\CoreBundle\Cron\Cron->run('web') #12 /home/www/contao-4.13/vendor/symfony/event-dispatcher/EventDispatcher.php(270): Contao\CoreBundle\EventListener\CommandSchedulerListener->__invoke(Object(Symfony\Component\HttpKernel\Event\TerminateEvent), 'kernel.terminat...', Object(Symfony\Component\EventDispatcher\EventDispatcher)) #13 /home/www/contao-4.13/vendor/symfony/event-dispatcher/EventDispatcher.php(230): Symfony\Component\EventDispatcher\EventDispatcher::Symfony\Component\EventDispatcher\{closure}(Object(Symfony\Component\HttpKernel\Event\TerminateEvent), 'kernel.terminat...', Object(Symfony\Component\EventDispatcher\EventDispatcher)) #14 /home/www/contao-4.13/vendor/symfony/event-dispatcher/EventDispatcher.php(59): Symfony\Component\EventDispatcher\EventDispatcher->callListeners(Array, 'kernel.terminat...', Object(Symfony\Component\HttpKernel\Event\TerminateEvent)) #15 /home/www/contao-4.13/vendor/symfony/http-kernel/HttpKernel.php(97): Symfony\Component\EventDispatcher\EventDispatcher->dispatch(Object(Symfony\Component\HttpKernel\Event\TerminateEvent), 'kernel.terminat...') #16 /home/www/contao-4.13/vendor/symfony/http-kernel/Kernel.php(159): Symfony\Component\HttpKernel\HttpKernel->terminate(Object(Symfony\Component\HttpFoundation\Request), Object(Symfony\Component\HttpFoundation\RedirectResponse)) #17 /home/www/contao-4.13/vendor/contao/manager-bundle/src/HttpKernel/ContaoCache.php(84): Symfony\Component\HttpKernel\Kernel->terminate(Object(Symfony\Component\HttpFoundation\Request), Object(Symfony\Component\HttpFoundation\RedirectResponse)) #18 /home/www/contao-4.13/public/index.php(48): Contao\ManagerBundle\HttpKernel\ContaoCache->terminate(Object(Symfony\Component\HttpFoundation\Request), Object(Symfony\Component\HttpFoundation\RedirectResponse)) #19 /home/www/contao-4.13/public/app.php(13): require('/home/www/conta...') #20 {main} [] []
[2024-01-04T10:06:48.366464+01:00] php.CRITICAL: Uncaught Exception: Failed to start the session because headers have already been sent by "/home/www/contao-4.13/vendor/symfony/http-foundation/Response.php" at line 381. {"exception":"[object] (RuntimeException(code: 0): Failed to start the session because headers have already been sent by \"/home/www/contao-4.13/vendor/symfony/http-foundation/Response.php\" at line 381. at /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php:145)"} []
[2024-01-04T10:06:48.366849+01:00] request.CRITICAL: Uncaught PHP Exception RuntimeException: "Failed to start the session because headers have already been sent by "/home/www/contao-4.13/vendor/symfony/http-foundation/Response.php" at line 381." at /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php line 145 {"exception":"[object] (RuntimeException(code: 0): Failed to start the session because headers have already been sent by \"/home/www/contao-4.13/vendor/symfony/http-foundation/Response.php\" at line 381. at /home/www/contao-4.13/vendor/symfony/http-foundation/Session/Storage/NativeSessionStorage.php:145)"} []

[Ruppel]

Hi,

finally found the reason for the frontend problem.

Had to go in the contao administration to "Layout">"Site structure" and edit the entry node. Set "URL settings">"Protocol" to "https://".
So the frontend is visible again.

But I still get the Internal Server Error in the backend...

Cheers,
Markus