diff --git a/examples/server/server.cpp b/examples/server/server.cpp
index 19bdca404..511972566 100644
--- a/examples/server/server.cpp
+++ b/examples/server/server.cpp
@@ -262,7 +262,7 @@ struct llama_server_context
         return true;
     }
 
-    void loadGrammar()
+    bool loadGrammar()
     {
         if (!params.grammar.empty()) {
             grammar_parser::parse_state parsed_grammar;
@@ -270,18 +270,15 @@ struct llama_server_context
             parsed_grammar = grammar_parser::parse(params.grammar.c_str());
             // will be empty (default) if there are parse errors
             if (parsed_grammar.rules.empty()) {
-                fprintf(stderr, "%s: grammar parse error\n", __func__);
-                return;
+                LOG_ERROR("grammar parse error", {{"grammar", params.grammar}});
+                return false;
             }
-            fprintf(stderr, "%s: grammar:\n", __func__);
             grammar_parser::print_grammar(stderr, parsed_grammar);
-            fprintf(stderr, "\n");
 
             {
                 auto it = params.logit_bias.find(llama_token_eos());
                 if (it != params.logit_bias.end() && it->second == -INFINITY) {
-                    fprintf(stderr,
-                        "%s: warning: EOS token is disabled, which will cause most grammars to fail\n", __func__);
+                    LOG_WARNING("EOS token is disabled, which will cause most grammars to fail", {});
                 }
             }
 
@@ -289,6 +286,7 @@ struct llama_server_context
             grammar = llama_grammar_init(
                 grammar_rules.data(), grammar_rules.size(), parsed_grammar.symbol_ids.at("root"));
         }
+        return true;
     }
 
     void loadPrompt()
@@ -1224,7 +1222,12 @@ int main(int argc, char **argv)
 
         parse_options_completion(json::parse(req.body), llama);
 
-        llama.loadGrammar();
+        if (!llama.loadGrammar())
+        {
+            res.status = 400;
+            return;
+        }
+
         llama.loadPrompt();
         llama.beginCompletion();
 
@@ -1376,8 +1379,12 @@ int main(int argc, char **argv)
 
     svr.set_error_handler([](const Request &, Response &res)
                           {
-        res.set_content("File Not Found", "text/plain");
-        res.status = 404; });
+        if (res.status == 400) {
+            res.set_content("Invalid request", "text/plain");
+        } else {
+            res.set_content("File Not Found", "text/plain");
+            res.status = 404; 
+        } });
 
     // set timeouts and change hostname and port
     svr.set_read_timeout(sparams.read_timeout);