diff --git a/pungi/checks.py b/pungi/checks.py
index ff38c6a3..e4d8dad1 100644
--- a/pungi/checks.py
+++ b/pungi/checks.py
@@ -200,6 +200,9 @@ def validate(config, offline=False):
         else:
             errors.append('Failed validation in %s: %s' % (
                 '.'.join([str(x) for x in error.path]), error.message))
+            if error.validator in ("anyOf", "oneOf"):
+                for suberror in error.context:
+                    errors.append("    Possible reason: %s" % suberror.message)
     return (errors + _validate_requires(schema, config, CONFIG_DEPS),
             warnings)
 
diff --git a/tests/test_osbs_phase.py b/tests/test_osbs_phase.py
index dd40ddaa..871e92d2 100644
--- a/tests/test_osbs_phase.py
+++ b/tests/test_osbs_phase.py
@@ -270,9 +270,13 @@ class OSBSThreadTest(helpers.PungiTestCase):
         config['osbs'] = {
             '^Server$': cfg
         }
-        self.assertEqual(
-            (['Failed validation in osbs.^Server$: %r is not valid under any of the given schemas' % cfg], []),
-            checks.validate(config, offline=True))
+        errors, warnings = checks.validate(config, offline=True)
+        self.assertIn(
+            "Failed validation in osbs.^Server$: %r is not valid under any of the given schemas" % cfg,
+            errors,
+        )
+        self.assertIn("    Possible reason: %r is a required property" % key, errors)
+        self.assertEqual([], warnings)
 
     @mock.patch('pungi.phases.osbs.kojiwrapper.KojiWrapper')
     def test_minimal_run(self, KojiWrapper):