diff --git a/lib/PushTransports/WebPushTransport.php b/lib/PushTransports/WebPushTransport.php
index 6a8f3f4..ebd638a 100644
--- a/lib/PushTransports/WebPushTransport.php
+++ b/lib/PushTransports/WebPushTransport.php
@@ -28,6 +28,7 @@ namespace OCA\DavPush\PushTransports;
 
 use OCA\DavPush\Transport\Transport;
 use OCA\DavPush\Service\WebPushSubscriptionService;
+use OCA\DavPush\Errors\WebPushSubscriptionNotFound;
 
 use Sabre\Xml\Service;
 
@@ -96,10 +97,14 @@ class WebPushTransport extends Transport {
 		$result = file_get_contents($data["pushResource"], false, $context);
 	}
 
-	public function getSubscriptionIdFromOptions($options): int {
+	public function getSubscriptionIdFromOptions($options): ?int {
 		['pushResource' => $pushResource] = $this->parseOptions($options);
 
-		return $this->webPushSubscriptionService->findByPushResource($pushResource)->getSubscriptionId();
+		try {
+			return $this->webPushSubscriptionService->findByPushResource($pushResource)->getSubscriptionId();
+		} catch (WebPushSubscriptionNotFound $e) {
+			return null;
+		}
 	}
 
 	public function updateSubscription($subsciptionId, $options) {
diff --git a/lib/Transport/Transport.php b/lib/Transport/Transport.php
index 5e36c85..eb4bce8 100644
--- a/lib/Transport/Transport.php
+++ b/lib/Transport/Transport.php
@@ -62,7 +62,7 @@ abstract class Transport {
 	// Transport needs to be able to map subscription options back to a subscription id.
 	// API Requests to create and update a subscription are the same, therefore if a subscription id is associated with the given options the subscription is updated, otherwise a new subscription is added.
 	// Which option(s) uniquely identify a subscription is implementation specific.
-	abstract public function getSubscriptionIdFromOptions($options): int;
+	abstract public function getSubscriptionIdFromOptions($options): ?int;
 
 	// Change mutable options of the subscription (if any exist)
 	abstract public function updateSubscription($subsciptionId, $options);