diff --git a/picomon/checks.py b/picomon/checks.py
index 6ffb5395bd62adb0a675c2e73a6188ad7b0b95aa..183b2f421006aa9dda0bb1d5fe383f2106e19841 100644
--- a/picomon/checks.py
+++ b/picomon/checks.py
@@ -314,7 +314,7 @@ class CheckTLSCert(Check):
     def build_command(self):
         command = ['/usr/lib/nagios/plugins/check_http',
                    '--ssl', '--sni',
-                   '-C', str(self._options.get('warn', 7),
+                   '-C', str(self._options.get('warn', 7)),
                    '-t', str(self.timeout)]
         if 'port' in self._options:
             command += ['-p', str(self._options['port'])]