Fix phone validation

api/v1/serializers/user.py

@@ -61,6 +61,11 @@ class UserSerializer(serializers.ModelSerializer):
             instance.save()
         return instance
 
+    def validate_phone(self, value):
+        if not value and value is not None:
+            value = None
+        return value
+
 
 class UserPhotoSerializer(serializers.Serializer):
     photo = Base64ImageField(