diff --git a/src/chall.rs b/src/chall.rs
index afe4684..e1db22b 100644
--- a/src/chall.rs
+++ b/src/chall.rs
@@ -22,9 +22,8 @@ impl Command for CommandImpl {
 
     fn run(&self, _arg_matches: &ArgMatches, sub_arg_matches: &ArgMatches) -> CommandError {
         let json_output = sub_arg_matches.is_present("json");
-        if json_output {
-            rust_util::util_msg::set_logger_std_out(false);
-        }
+        if json_output { rust_util::util_msg::set_logger_std_out(false); }
+        
         let sha256_output = sub_arg_matches.is_present("sha256");
         let sha384_output = sub_arg_matches.is_present("sha384");
         let sha512_output = sub_arg_matches.is_present("sha512");
@@ -32,7 +31,7 @@ impl Command for CommandImpl {
         if let Some(challenge) = sub_arg_matches.value_of("challenge") {
             challenge_bytes = challenge.as_bytes().to_vec();
         } else if let Some(challenge_hex) = sub_arg_matches.value_of("challenge-hex") {
-            challenge_bytes = hex::decode(challenge_hex)?;
+            challenge_bytes = opt_result!(hex::decode(challenge_hex), "Decode challenge hex: {}, failed: {}", challenge_hex);
         } else {
             return simple_error!("Challenge must assigned");
         }