Error when creating new user

Whenever i try to generate a new user i get an error saying "cannot continue" (in German "Es ist ein Fehler bei der Anfrage aufgetreten. Es kann nicht fortgefahren werden").
When i then close the "generate user window" the user is in fact generated but without email adress.

I run Nextcloud Hub 6 (27.1.2) in Docker.
It is a fresh install.

This is what i see in the error log:

[no app in context] Fehler: Exception: OCA\Circles\Tools\Model\Request::setHost(): Argument #1 ($host) must be of type string, null given, called in /config/www/nextcloud/apps/circles/lib/Tools/Model/Request.php on line 296 in file '/config/www/nextcloud/apps/circles/lib/Tools/Model/Request.php' line 206 at <<closure>>

0. /app/www/public/lib/private/AppFramework/App.php line 183
   OC\AppFramework\Http\Dispatcher->dispatch()
1. /app/www/public/lib/private/Route/Router.php line 315
   OC\AppFramework\App::main()
2. /app/www/public/ocs/v1.php line 64
   OC\Route\Router->match()
3. /app/www/public/ocs/v2.php line 23
   require_once("/app/www/public/ocs/v1.php")

Caused by:

TypeError: OCA\Circles\Tools\Model\Request::setHost(): Argument #1 ($host) must be of type string, null given, called in /config/www/nextcloud/apps/circles/lib/Tools/Model/Request.php on line 296 at <<closure>>

 0. /config/www/nextcloud/apps/circles/lib/Tools/Model/Request.php line 296
    OCA\Circles\Tools\Model\Request->setHost()
 1. /config/www/nextcloud/apps/circles/lib/Service/ConfigService.php line 737
    OCA\Circles\Tools\Model\Request->basedOnUrl()
 2. /config/www/nextcloud/apps/circles/lib/Service/FederatedEventService.php line 434
    OCA\Circles\Service\ConfigService->configureLoopbackRequest()
 3. /config/www/nextcloud/apps/circles/lib/Service/FederatedEventService.php line 188
    OCA\Circles\Service\FederatedEventService->initBroadcast()
 4. /config/www/nextcloud/apps/circles/lib/Service/SyncService.php line 454
    OCA\Circles\Service\FederatedEventService->newEvent()
 5. /config/www/nextcloud/apps/circles/lib/Listeners/GroupMemberAdded.php line 71
    OCA\Circles\Service\SyncService->groupMemberAdded()
 6. /app/www/public/lib/private/EventDispatcher/ServiceEventListener.php line 86
    OCA\Circles\Listeners\GroupMemberAdded->handle()
 7. /app/www/public/3rdparty/symfony/event-dispatcher/EventDispatcher.php line 251
    OC\EventDispatcher\ServiceEventListener->__invoke()
 8. /app/www/public/3rdparty/symfony/event-dispatcher/EventDispatcher.php line 73
    Symfony\Component\EventDispatcher\EventDispatcher->callListeners()
 9. /app/www/public/lib/private/EventDispatcher/EventDispatcher.php line 94
    Symfony\Component\EventDispatcher\EventDispatcher->dispatch()
10. /app/www/public/lib/private/EventDispatcher/EventDispatcher.php line 106
    OC\EventDispatcher\EventDispatcher->dispatch()
11. /app/www/public/lib/private/Server.php line 530
    OC\EventDispatcher\EventDispatcher->dispatchTyped()
12. <<closure>>
    OC\Server->OC\{closure}("*** sensitive parameters replaced ***")
13. /app/www/public/lib/private/Hooks/EmitterTrait.php line 105
    call_user_func_array()
14. /app/www/public/lib/private/Hooks/PublicEmitter.php line 40
    OC\Hooks\BasicEmitter->emit()
15. /app/www/public/lib/private/Group/Group.php line 202
    OC\Hooks\PublicEmitter->emit()
16. /config/www/nextcloud/apps/provisioning_api/lib/Controller/UsersController.php line 425
    OC\Group\Group->addUser("*** sensitive parameters replaced ***")
17. /app/www/public/lib/private/AppFramework/Http/Dispatcher.php line 230
    OCA\Provisioning_API\Controller\UsersController->addUser("*** sensitive parameters replaced ***")
18. /app/www/public/lib/private/AppFramework/Http/Dispatcher.php line 137
    OC\AppFramework\Http\Dispatcher->executeController()
19. /app/www/public/lib/private/AppFramework/App.php line 183
    OC\AppFramework\Http\Dispatcher->dispatch()
20. /app/www/public/lib/private/Route/Router.php line 315
    OC\AppFramework\App::main()
21. /app/www/public/ocs/v1.php line 64
    OC\Route\Router->match()
22. /app/www/public/ocs/v2.php line 23
    require_once("/app/www/public/ocs/v1.php")

POST /ocs/v2.php/cloud/users
from 94.31.98.109 by mon at 2023-11-30T12:27:16+00:00

Start by reproducing user creation in the Docker-based Nextcloud setup, then trace the stack from provisioning_api/lib/Controller/UsersController.php line 425 through circles/lib/Service/FederatedEventService.php line 434 and ConfigService.php line 737. Inspect circles/lib/Tools/Model/Request.php at lines 206 and 296; done means user creation no longer reports the error and the email address is retained.