diff --git a/source/changelog.txt b/source/changelog.txt
index 8c35d3a..5010b98 100644
--- a/source/changelog.txt
+++ b/source/changelog.txt
@@ -4,6 +4,7 @@
 #### Deprecated
 #### Removed
 #### Fixed
+- Fix undefined variable $classNamePrefix for both error views
 #### Security
 
 ### [1.0.0]
diff --git a/source/includes/EventsListBlock.php b/source/includes/EventsListBlock.php
index 478b599..5810587 100644
--- a/source/includes/EventsListBlock.php
+++ b/source/includes/EventsListBlock.php
@@ -39,6 +39,7 @@ class EventsListBlock {
     $url = Settings::getUrl();
     $eventsCount = $block_attributes['eventsCount'];
     $groupName = isset($block_attributes['groupName']) ? $block_attributes['groupName'] : '';
+    $classNamePrefix = NAME;
 
     ob_start();
     try {
@@ -48,7 +49,6 @@ class EventsListBlock {
         $events = GraphQlClient::get_upcoming_events($url, (int) $eventsCount);
       }
 
-      $classNamePrefix = NAME;
       $locale = get_locale();
       $isShortOffsetNameShown = Settings::isShortOffsetNameShown();
       $timeZone = wp_timezone_string();
diff --git a/source/includes/EventsListShortcut.php b/source/includes/EventsListShortcut.php
index ce1e529..0a2024d 100644
--- a/source/includes/EventsListShortcut.php
+++ b/source/includes/EventsListShortcut.php
@@ -22,6 +22,7 @@ class EventsListShortcut {
     $url = Settings::getUrl();
     $eventsCount = $atts_with_overriden_defaults['events-count'];
     $groupName = $atts_with_overriden_defaults['group-name'];
+    $classNamePrefix = NAME;
 
     ob_start();
     try {
@@ -31,7 +32,6 @@ class EventsListShortcut {
         $events = GraphQlClient::get_upcoming_events($url, (int) $eventsCount);
       }
 
-      $classNamePrefix = NAME;
       $locale = get_locale();
       $isShortOffsetNameShown = Settings::isShortOffsetNameShown();
       $timeZone = wp_timezone_string();
diff --git a/source/includes/EventsListWidget.php b/source/includes/EventsListWidget.php
index 5503cff..68876ab 100644
--- a/source/includes/EventsListWidget.php
+++ b/source/includes/EventsListWidget.php
@@ -23,6 +23,7 @@ class EventsListWidget extends \WP_Widget {
     $url = Settings::getUrl();
     $eventsCount = $options['eventsCount'];
     $groupName = isset($options['groupName']) ? $options['groupName'] : '';
+    $classNamePrefix = NAME;
 
     try {
       if ($groupName) {
@@ -31,7 +32,6 @@ class EventsListWidget extends \WP_Widget {
         $events = GraphQlClient::get_upcoming_events($url, (int) $eventsCount);
       }
 
-      $classNamePrefix = NAME;
       $locale = get_locale();
       $isShortOffsetNameShown = Settings::isShortOffsetNameShown();
       $timeZone = wp_timezone_string();