diff --git a/shared-libs/outbound/src/outbound.js b/shared-libs/outbound/src/outbound.js
index 9fbc6efc58..f7ac203eb5 100644
--- a/shared-libs/outbound/src/outbound.js
+++ b/shared-libs/outbound/src/outbound.js
@@ -69,12 +69,14 @@ const mapDocumentToPayload = (doc, config, key) => {
       } catch (err) {
         throw new OutboundError(`Mapping error for '${key}/${dest}' JS error on source document: '${doc._id}': ${err}`);
       }
-    } else {
+    } else if (path) {
       try {
         srcValue = objectPath.get({doc}, path);
       } catch (err) {
         throw new OutboundError(`Mapping error for '${key}/${dest}' JS error on source document: '${doc._id}': ${err}`);
       }
+    } else {
+      throw new OutboundError(`Mapping error for '${key}/${dest}' either 'expr' or 'path' is required: '${doc._id}'`);
     }
 
     if (required && srcValue === undefined) {
diff --git a/shared-libs/outbound/test/outbound.spec.js b/shared-libs/outbound/test/outbound.spec.js
index 5a706965cb..948351d898 100644
--- a/shared-libs/outbound/test/outbound.spec.js
+++ b/shared-libs/outbound/test/outbound.spec.js
@@ -210,6 +210,20 @@ describe('outbound shared library', () => {
 
       assert.throws(() => mapDocumentToPayload(doc, conf, 'test-doc'), /Mapping error/);
     });
+
+    it('throws an exception if the expression does not have either path or expr', () => {
+      const doc = {
+        _id: 'test-doc',
+      };
+
+      const conf = {
+        mapping: {
+          is_gonna_fail: {not_path_or_expr: 'doc.fields.null.pointer'},
+        }
+      };
+
+      assert.throws(() => mapDocumentToPayload(doc, conf, 'test-doc'), /Mapping error.*'expr' or 'path' is required/);
+    });
   });
 
   describe('updateInfo', () => {