diff --git a/languages/config-expander-nl_NL.mo b/languages/config-expander-nl_NL.mo
index dc3118c..1da1450 100644
Binary files a/languages/config-expander-nl_NL.mo and b/languages/config-expander-nl_NL.mo differ
diff --git a/languages/config-expander-nl_NL.po b/languages/config-expander-nl_NL.po
index 48bfe4c..583456e 100644
--- a/languages/config-expander-nl_NL.po
+++ b/languages/config-expander-nl_NL.po
@@ -19,6 +19,19 @@ msgstr "De vereiste plugin voor de Config Expander package <strong>Advanced Cust
 msgid "This link does not work, go to our website: <a href=\"%s\">%s</a>."
 msgstr "Deze link bestaat niet, ga naar onze website: <a href=\"%s\">%s</a>."
 
-#: src/Protection/Protect.php:80
+#: src/Protection/Protect.php:89
 msgid "Viewing this page requires a login session. Please log in first."
 msgstr "Het bekijken van deze pagina vereist een login sessie. Graag eerst inloggen."
+
+#. translators: %s: visitor IP address
+#: src/Protection/Protect.php:97
+msgid "Your IP address is %s. Please contact the administrator to request a whitelist."
+msgstr "Jouw IP-adres is %s. Neem contact op met de beheerder om een whitelist aan te vragen."
+
+#: src/Protection/Protect.php:104
+msgid "Access Denied"
+msgstr "Toegang geweigerd"
+
+#: src/Protection/Protect.php:108
+msgid "Go to login page"
+msgstr "Ga naar de inlogpagina"
diff --git a/languages/config-expander.pot b/languages/config-expander.pot
index a8d32d7..8579935 100644
--- a/languages/config-expander.pot
+++ b/languages/config-expander.pot
@@ -20,6 +20,19 @@ msgstr ""
 msgid "This link does not work, go to our website: <a href=\"%s\">%s</a>."
 msgstr ""
 
-#: src/Protection/Protect.php:80
-msgid "You're not allowed to view this page."
+#: src/Protection/Protect.php:89
+msgid "Viewing this page requires a login session. Please log in first."
+msgstr ""
+
+#. translators: %s: visitor IP address
+#: src/Protection/Protect.php:97
+msgid "Your IP address is %s. Please contact the administrator to request a whitelist."
+msgstr ""
+
+#: src/Protection/Protect.php:104
+msgid "Access Denied"
+msgstr ""
+
+#: src/Protection/Protect.php:108
+msgid "Go to login page"
 msgstr ""
diff --git a/src/ACF/ACFServiceProvider.php b/src/ACF/ACFServiceProvider.php
index ee16a1d..bc2b7f3 100644
--- a/src/ACF/ACFServiceProvider.php
+++ b/src/ACF/ACFServiceProvider.php
@@ -134,6 +134,26 @@ public function addLocalFieldGroup(): void
 					'ajax' => 0,
 					'placeholder' => '',
 				],
+				[
+					'key' => 'field_666962be81793',
+					'label' => 'Toon IP bij geweigerde toegang',
+					'name' => 'show_ip_on_deny',
+					'aria-label' => '',
+					'type' => 'true_false',
+					'instructions' => 'Toon het IP-adres van de bezoeker bij geweigerde toegang.',
+					'required' => 0,
+					'conditional_logic' => 0,
+					'wrapper' => [
+						'width' => '',
+						'class' => '',
+						'id' => '',
+					],
+					'message' => '',
+					'default_value' => 0,
+					'ui' => 1,
+					'ui_on_text' => 'Aan',
+					'ui_off_text' => 'Uit',
+				],
 				[
 					'key' => 'field_666845f07125a',
 					'label' => 'IP-adres whitelist',
diff --git a/src/Protection/Protect.php b/src/Protection/Protect.php
index 0a22983..4e63195 100644
--- a/src/Protection/Protect.php
+++ b/src/Protection/Protect.php
@@ -37,7 +37,7 @@ protected function authorizeAccess(string $type): void
 	 */
 	protected function setNoCacheHeader(): void
 	{
-		header('Cache-Control: no-cache');
+		nocache_headers();
 	}
 
 	protected function checkIfVisitorHasAccess(string $type): bool
@@ -86,9 +86,28 @@ protected function currentProtectionTypeMatchesWhitelist(string $type, Whitelist
 
 	protected function denyAccess(): void
 	{
-		header('HTTP/1.0 401 Unauthorized');
-		echo __('Viewing this page requires a login session. Please log in first.', 'config-expander');
-		exit;
+		$message = __('Viewing this page requires a login session. Please log in first.', 'config-expander');
+
+		$showIp = function_exists('get_field') && (bool) get_field('show_ip_on_deny', 'options');
+		$loginProtected = function_exists('get_field') && in_array(get_field('type_protection_website', 'options'), ['login', 'both'], true);
+
+		if ($showIp && $loginProtected) {
+			$message .= ' ' . sprintf(
+				/* translators: %s: visitor IP address */
+				__('Your IP address is %s. Please contact the administrator to request a whitelist.', 'config-expander'),
+				esc_html($this->ipCurrentVisitor())
+			);
+		}
+
+		wp_die(
+			$message,
+			__('Access Denied', 'config-expander'),
+			[
+				'response' => 401,
+				'link_url' => wp_login_url(),
+				'link_text' => __('Go to login page', 'config-expander'),
+			]
+		);
 	}
 
 	protected function ipCurrentVisitor(): string