diff --git a/src/tools/chip-cert/Cmd_GenCert.cpp b/src/tools/chip-cert/Cmd_GenCert.cpp
index 9c085846663a1f..d9f3a9a422ec79 100644
--- a/src/tools/chip-cert/Cmd_GenCert.cpp
+++ b/src/tools/chip-cert/Cmd_GenCert.cpp
@@ -268,7 +268,7 @@ bool HandleOption(const char * progName, OptionSet * optSet, int id, const char
         break;
 
     case 'a':
-        if (!ParseInt(arg, chip32bitAttr, 16) || chip::IsValidCASEAuthTag(chip32bitAttr))
+        if (!ParseInt(arg, chip32bitAttr, 16) || !chip::IsValidCASEAuthTag(chip32bitAttr))
         {
             PrintArgError("%s: Invalid value specified for the subject CASE Authenticated Tag (CAT) attribute: %s\n", progName,
                           arg);