diff --git a/connexion/spec.py b/connexion/spec.py
index 40fe46d70..ca40714f2 100644
--- a/connexion/spec.py
+++ b/connexion/spec.py
@@ -204,7 +204,10 @@ def enforce_string_keys(obj):
         return OpenAPISpecification(spec, base_uri=base_uri)
 
     def clone(self):
-        return type(self)(copy.deepcopy(self._raw_spec))
+        try:
+            return type(self)(copy.deepcopy(self._raw_spec))
+        except jsonschema.exceptions.RefResolutionError:
+            return type(self)(copy.deepcopy(self._spec))
 
     @classmethod
     def load(cls, spec, *, arguments=None):
diff --git a/tests/fixtures/simple/foo.yaml b/tests/fixtures/simple/foo.yaml
new file mode 100644
index 000000000..80cd1bd1c
--- /dev/null
+++ b/tests/fixtures/simple/foo.yaml
@@ -0,0 +1,7 @@
+title: foo
+type: object
+properties:
+  foo:
+    type: string
+  foo4:
+    type: string
diff --git a/tests/fixtures/simple/openapi.yaml b/tests/fixtures/simple/openapi.yaml
index c4ce61773..4eb59aab1 100644
--- a/tests/fixtures/simple/openapi.yaml
+++ b/tests/fixtures/simple/openapi.yaml
@@ -180,12 +180,7 @@ paths:
           content:
             application/json:
               schema:
-                type: object
-                properties:
-                  foo:
-                    type: string
-                  foo4:
-                    type: string
+                $ref: ./foo.yaml
   /exploded-deep-object-param-additional-properties:
     get:
       summary: Returns dict response with flexible properties