diff --git a/src/python/CRABClient/ProxyInteractions.py b/src/python/CRABClient/ProxyInteractions.py
index 1fc5792a..627a3686 100644
--- a/src/python/CRABClient/ProxyInteractions.py
+++ b/src/python/CRABClient/ProxyInteractions.py
@@ -62,7 +62,7 @@ def validateVO(self):
         # make sure that proxy has a VOMS extension for CMS VirtualOrganization
         cmd = 'voms-proxy-info --vo --file %s' % self.proxyFile
         stdout, stderr, rc = execute_command(cmd, logger=self.logger)
-        if rc != 0 or stdout != 'cms':
+        if rc != 0 or 'cms' not in stdout:
             msg = "\n".join(['Error executing %s:' % cmd, stdout, stderr])
             self.logger.error(msg)
             msg = 'proxy %s is not a valid proxy file or has no valid VOMS extension.\n' % self.proxyFile