diff --git saml/univention-saml/listener/univention-saml-groups.py saml/univention-saml/listener/univention-saml-groups.py
index 7b60fc7f90..f9c72d96d9 100644
--- saml/univention-saml/listener/univention-saml-groups.py
+++ saml/univention-saml/listener/univention-saml-groups.py
@@ -82,7 +82,7 @@ def handler(dn, new, old):
 				if sp not in data:
 					data[sp] = []
 				if sp in data[sp]:
-					data[sp].pop(sp)
+					data[sp].remove(sp)
 
 		with open(tmp_path, 'w+') as outfile:
 			json.dump(data, outfile)