log error messgage

Signed-off-by: Bjoern Schiessle <bjoern@schiessle.org>

lib/private/Federation/CloudFederationProviderManager.php

@@ -157,6 +157,7 @@ class CloudFederationProviderManager implements ICloudFederationProviderManager
 			// we re-throw the exception and fall back to the old behaviour.
 			// (flat re-shares has been introduced in Nextcloud 9.1)
 			if ($e->getCode() === Http::STATUS_INTERNAL_SERVER_ERROR) {
+				$this->logger->debug($e->getMessage());
 				throw $e;
 			}
 		}