diff --git a/src/Concerns/Relationships.php b/src/Concerns/Relationships.php
index 6fe442d..471414e 100644
--- a/src/Concerns/Relationships.php
+++ b/src/Concerns/Relationships.php
@@ -144,7 +144,7 @@ private function resolveRelationships(Request $request)
                 $value => self::guessRelationshipResource($value, $this),
             ])
             ->map(fn (string $class, string $relation): Closure => function () use ($class, $relation): JsonApiResource|JsonApiResourceCollection {
-                return with($this->resource->{$relation}, function (mixed $resource) use ($class): JsonApiResource|JsonApiResourceCollection {
+                return with($this->resource?->{$relation}, function (mixed $resource) use ($class): JsonApiResource|JsonApiResourceCollection {
                     if ($resource instanceof Traversable || (is_array($resource) && ! Arr::isAssoc($resource))) {
                         return $class::collection($resource);
                     }