diff --git a/lti_consumer/lti_1p3/consumer.py b/lti_consumer/lti_1p3/consumer.py
index 32a618fc..52caa740 100644
--- a/lti_consumer/lti_1p3/consumer.py
+++ b/lti_consumer/lti_1p3/consumer.py
@@ -716,7 +716,7 @@ def check_and_decode_deep_linking_token(self, token):
 
         # Check the response is a Deep Linking response type
         message_type = deep_link_response.get("https://purl.imsglobal.org/spec/lti/claim/message_type")
-        if not message_type == "LtiDeepLinkingResponse":
+        if not (isinstance(message_type, str) and message_type.lower() == "ltideeplinkingresponse"):
             raise exceptions.InvalidClaimValue("Token isn't a Deep Linking Response message.")
 
         # Check if supported contentitems were returned