diff --git a/proxy/http/remap/RemapConfig.cc b/proxy/http/remap/RemapConfig.cc
index 6a33352ad2a..a5948ee8691 100644
--- a/proxy/http/remap/RemapConfig.cc
+++ b/proxy/http/remap/RemapConfig.cc
@@ -669,6 +669,8 @@ remap_check_option(const char **argv, int argc, unsigned long findmode, int *_re
           idx = i;
         }
         ret_flags |= REMAP_OPTFLG_INTERNAL;
+      } else {
+        TSError("remap_check_option(): Option '%s' in remap configuration is not valid.\n", argv[i]);
       }
 
       if ((findmode & ret_flags) && !argptr) {