diff --git a/src/challenge-module/challenge-email.cpp b/src/challenge-module/challenge-email.cpp
index 4ec3c6f..c1e498a 100644
--- a/src/challenge-module/challenge-email.cpp
+++ b/src/challenge-module/challenge-email.cpp
@@ -219,7 +219,7 @@
 {
   std::string command = m_sendEmailScript;
   command += " \"" + emailAddress + "\" \"" + secret + "\" \""
-    + request.m_caName.toUri() + "\" \"" + request.m_cert.getName().toUri()  + "\"";
+    + request.m_caPrefix.toUri() + "\" \"" + request.m_cert.getName().toUri()  + "\"";
   int result = system(command.c_str());
   if (result == -1) {
     _LOG_TRACE("EmailSending Script " + m_sendEmailScript + " fails.");