diff --git a/includes/class-twp-agent-manager.php b/includes/class-twp-agent-manager.php
index 02cb48c..54ce692 100644
--- a/includes/class-twp-agent-manager.php
+++ b/includes/class-twp-agent-manager.php
@@ -283,7 +283,12 @@ class TWP_Agent_Manager {
         if ($call_mode === 'browser') {
             // For browser mode, redirect the existing call to the browser client
             $current_user = get_userdata($user_id);
-            $client_name = 'agent_' . $user_id . '_' . sanitize_title($current_user->display_name);
+            // Twilio requires alphanumeric characters only - must match generate_capability_token
+            $clean_name = preg_replace('/[^a-zA-Z0-9]/', '', $current_user->display_name);
+            if (empty($clean_name)) {
+                $clean_name = 'user';
+            }
+            $client_name = 'agent' . $user_id . $clean_name;
             
             // Create TwiML to redirect call to browser client
             $twiml = new \Twilio\TwiML\VoiceResponse();
diff --git a/includes/class-twp-webhooks.php b/includes/class-twp-webhooks.php
index 18a9b7b..1a56897 100644
--- a/includes/class-twp-webhooks.php
+++ b/includes/class-twp-webhooks.php
@@ -408,7 +408,12 @@ class TWP_Webhooks {
             $agent_phone = get_user_meta($agent->ID, 'twp_phone_number', true);
             
             if ($call_mode === 'browser') {
-                $client_name = 'agent_' . $agent->ID . '_' . sanitize_title($agent->display_name);
+                // Twilio requires alphanumeric characters only
+                $clean_name = preg_replace('/[^a-zA-Z0-9]/', '', $agent->display_name);
+                if (empty($clean_name)) {
+                    $clean_name = 'user';
+                }
+                $client_name = 'agent' . $agent->ID . $clean_name;
                 $browser_agents[] = $client_name;
             } elseif (!empty($agent_phone)) {
                 $cell_agents[] = $agent_phone;
@@ -485,7 +490,12 @@ class TWP_Webhooks {
             $agent_phone = get_user_meta($agent->ID, 'twp_phone_number', true);
             
             if ($call_mode === 'browser') {
-                $client_name = 'agent_' . $agent->ID . '_' . sanitize_title($agent->display_name);
+                // Twilio requires alphanumeric characters only
+                $clean_name = preg_replace('/[^a-zA-Z0-9]/', '', $agent->display_name);
+                if (empty($clean_name)) {
+                    $clean_name = 'user';
+                }
+                $client_name = 'agent' . $agent->ID . $clean_name;
                 $browser_agents[] = $client_name;
             } elseif (!empty($agent_phone)) {
                 $cell_agents[] = $agent_phone;
diff --git a/includes/class-twp-workflow.php b/includes/class-twp-workflow.php
index 9bdca6d..6ee9d95 100644
--- a/includes/class-twp-workflow.php
+++ b/includes/class-twp-workflow.php
@@ -458,7 +458,12 @@ class TWP_Workflow {
             ));
             
             foreach ($agents as $agent) {
-                $client_name = 'agent_' . $agent->ID . '_' . sanitize_title($agent->display_name);
+                // Twilio requires alphanumeric characters only
+                $clean_name = preg_replace('/[^a-zA-Z0-9]/', '', $agent->display_name);
+                if (empty($clean_name)) {
+                    $clean_name = 'user';
+                }
+                $client_name = 'agent' . $agent->ID . $clean_name;
                 $client = $dial->addChild('Client', $client_name);
             }
         } else {