diff --git a/slixmpp/xmlstream/xmlstream.py b/slixmpp/xmlstream/xmlstream.py
index 9077f23c..a687c4f6 100644
--- a/slixmpp/xmlstream/xmlstream.py
+++ b/slixmpp/xmlstream/xmlstream.py
@@ -35,6 +35,7 @@ import ssl
 import uuid
 import warnings
 import weakref
+import collections
 
 from contextlib import contextmanager
 import xml.etree.ElementTree as ET
@@ -82,7 +83,7 @@ class InvalidCABundle(Exception):
         Exception raised when the CA Bundle file hasn't been found.
     """
 
-    def __init__(self, path: Optional[Path]):
+    def __init__(self, path: Optional[Union[Path, Iterable[Path]]]):
         self.path = path
 
 
@@ -793,8 +794,9 @@ class XMLStream(asyncio.BaseProtocol):
                     if bundle.is_file():
                         ca_cert = bundle
                         break
-            if ca_cert is None:
-                raise InvalidCABundle(ca_cert)
+            if ca_cert is None and \
+               isinstance(self.ca_certs, (Path, collections.abc.Iterable)):
+                raise InvalidCABundle(self.ca_certs)
 
             self.ssl_context.verify_mode = ssl.CERT_REQUIRED
             self.ssl_context.load_verify_locations(cafile=ca_cert)