diff --git a/src/idpyoidc/server/client_authn.py b/src/idpyoidc/server/client_authn.py
index 60370b0e..06321c0a 100755
--- a/src/idpyoidc/server/client_authn.py
+++ b/src/idpyoidc/server/client_authn.py
@@ -512,7 +512,10 @@ def verify_client(
         if _get_client_info:
             _cinfo = _get_client_info(client_id, _context)
         else:
-            _cinfo = _context.cdb[client_id]
+            try:
+                _cinfo = _context.cdb[client_id]
+            except KeyError:
+                raise UnknownClient("Unknown Client ID")
 
         if not _cinfo:
             raise UnknownClient("Unknown Client ID")
diff --git a/src/idpyoidc/server/oauth2/add_on/pkce.py b/src/idpyoidc/server/oauth2/add_on/pkce.py
index ce44aaed..0b1e697a 100644
--- a/src/idpyoidc/server/oauth2/add_on/pkce.py
+++ b/src/idpyoidc/server/oauth2/add_on/pkce.py
@@ -8,6 +8,7 @@
 from idpyoidc.message.oauth2 import AuthorizationErrorResponse
 from idpyoidc.message.oauth2 import RefreshAccessTokenRequest
 from idpyoidc.message.oauth2 import TokenExchangeRequest
+from idpyoidc.message.oauth2 import CCAccessTokenRequest
 from idpyoidc.message.oidc import TokenErrorResponse
 from idpyoidc.server.endpoint import Endpoint
 
@@ -93,7 +94,7 @@ def post_token_parse(request, client_id, context, **kwargs):
     """
     if isinstance(
         request,
-        (AuthorizationErrorResponse, RefreshAccessTokenRequest, TokenExchangeRequest),
+        (AuthorizationErrorResponse, RefreshAccessTokenRequest, TokenExchangeRequest, CCAccessTokenRequest),
     ):
         return request