diff --git a/qrexec/tools/qrexec_policy_agent.py b/qrexec/tools/qrexec_policy_agent.py
index 0d8b724e..dd7b55db 100644
--- a/qrexec/tools/qrexec_policy_agent.py
+++ b/qrexec/tools/qrexec_policy_agent.py
@@ -437,7 +437,7 @@ def __init__(
     ):
         # pylint: disable=too-many-arguments
         sanitize_domain_name(source, assert_sanitized=True)
-        sanitize_service_name(source, assert_sanitized=True)
+        sanitize_service_name(service, assert_sanitized=True)
 
         self._gtk_builder = Gtk.Builder()
         with importlib.resources.as_file(self._source_file_ref) as path: