Unable to connect to built-in CODE server (GuzzleHttp exception)

Installation & Configuration
1

I’m trying to use the built-in CODE server for a small installation (x86_64). I’ve installed both richdocuments and richdocumentscode, and have Nextcloud Office pointing to use the built-in server. When navigating to the admin page for Nextcloud Office, I receive the error message that it cannot connect to the built-in server, giving me the this link to verify that this location block is configured correctly.

I then restart nginx and php-fpm, and still receive the same error. Going to the logging page shows a constant stream of the following error multiple times per second:

[richdocuments] Error: GuzzleHttp\Exception\RequestException: An error was encountered while creating the response at <>

  1. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Handler/CurlFactory.php line 158
    GuzzleHttp\Handler\CurlFactory::createRejection()
  2. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Handler/CurlFactory.php line 110
    GuzzleHttp\Handler\CurlFactory::finishError()
  3. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Handler/CurlHandler.php line 47
    GuzzleHttp\Handler\CurlFactory::finish()
  4. /var/www/html/lib/private/Http/Client/DnsPinMiddleware.php line 114
    GuzzleHttp\Handler\CurlHandler->__invoke()
  5. /var/www/html/3rdparty/guzzlehttp/guzzle/src/PrepareBodyMiddleware.php line 35
    OC\Http\Client\DnsPinMiddleware->OC\Http\Client{closure}(“*** sensitive parameters replaced ***”)
  6. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Middleware.php line 31
    GuzzleHttp\PrepareBodyMiddleware->__invoke()
  7. /var/www/html/3rdparty/guzzlehttp/guzzle/src/RedirectMiddleware.php line 71
    GuzzleHttp\Middleware::GuzzleHttp{closure}(“*** sensitive parameters replaced ***”)
  8. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Middleware.php line 63
    GuzzleHttp\RedirectMiddleware->__invoke()
  9. /var/www/html/3rdparty/guzzlehttp/guzzle/src/HandlerStack.php line 75
    GuzzleHttp\Middleware::GuzzleHttp{closure}(“*** sensitive parameters replaced ***”)
  10. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Client.php line 331
    GuzzleHttp\HandlerStack->__invoke()
  11. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Client.php line 168
    GuzzleHttp\Client->transfer()
  12. /var/www/html/3rdparty/guzzlehttp/guzzle/src/Client.php line 187
    GuzzleHttp\Client->requestAsync()
  13. /var/www/html/lib/private/Http/Client/Client.php line 218
    GuzzleHttp\Client->request()
  14. /var/www/html/apps/richdocuments/lib/Service/CapabilitiesService.php line 136
    OC\Http\Client\Client->get()
  15. /var/www/html/apps/richdocuments/lib/Service/CapabilitiesService.php line 74
    OCA\Richdocuments\Service\CapabilitiesService->refetch()
  16. /var/www/html/apps/richdocuments/lib/AppInfo/Application.php line 80
    OCA\Richdocuments\Service\CapabilitiesService->getCapabilities()
  17. /var/www/html/lib/private/AppFramework/Bootstrap/FunctionInjector.php line 67
    OCA\Richdocuments\AppInfo\Application->OCA\Richdocuments\AppInfo{closure}(“*** sensitive parameters replaced ***”)
  18. /var/www/html/lib/private/AppFramework/Bootstrap/BootContext.php line 51
    OC\AppFramework\Bootstrap\FunctionInjector->injectFn()
  19. /var/www/html/apps/richdocuments/lib/AppInfo/Application.php line 135
    OC\AppFramework\Bootstrap\BootContext->injectFn()
  20. /var/www/html/lib/private/AppFramework/Bootstrap/Coordinator.php line 190
    OCA\Richdocuments\AppInfo\Application->boot()
  21. /var/www/html/lib/private/legacy/OC_App.php line 208
    OC\AppFramework\Bootstrap\Coordinator->bootApp()
  22. /var/www/html/lib/private/legacy/OC_App.php line 141
    OC_App::loadApp()
  23. /var/www/html/lib/base.php line 1033
    OC_App::loadApps()
  24. /var/www/html/index.php line 36
    OC::handleRequest()

GET /apps/logreader/poll?lastReqId=2BBD23siYGR3yzDr8Tol
from $IP by $USER at 2023-10-18T18:29:53+00:00

Is there anything I could be missing that would cause Nextcloud to not connect to the server?