diff --git a/news/1913.bugfix b/news/1913.bugfix
new file mode 100644
index 0000000000..48d767383e
--- /dev/null
+++ b/news/1913.bugfix
@@ -0,0 +1,2 @@
+Fix error serializing empty reference from Archetypes content.
+[maurits]
diff --git a/src/plone/restapi/serializer/atfields.py b/src/plone/restapi/serializer/atfields.py
index 461cb14411..95c94fc2dd 100644
--- a/src/plone/restapi/serializer/atfields.py
+++ b/src/plone/restapi/serializer/atfields.py
@@ -126,7 +126,7 @@ def __call__(self):
         accessor = self.field.getAccessor(self.context)
         refs = accessor()
         if self.field.multiValued:
-            return [json_compatible(r.absolute_url()) for r in refs]
+            return [json_compatible(r.absolute_url()) for r in refs if r is not None]
         else:
             if refs is None:
                 return None