diff --git a/files/lib/data/message/MessageAction.class.php b/files/lib/data/message/MessageAction.class.php
index 795240a..28c8e88 100644
--- a/files/lib/data/message/MessageAction.class.php
+++ b/files/lib/data/message/MessageAction.class.php
@@ -5,7 +5,7 @@
  * Use of this software is governed by the Business Source License
  * included in the LICENSE file.
  *
- * Change Date: 2024-11-01
+ * Change Date: 2024-11-02
  *
  * On the date above, in accordance with the Business Source
  * License, use of this software will be governed by version 2
@@ -318,6 +318,8 @@ class MessageAction extends \wcf\data\AbstractDatabaseObjectAction {
 		$user = new \chat\data\user\User(WCF::getUser());
 		if (!$user->isInRoom($room)) throw new PermissionDeniedException();
 
+		if (!$room->canWritePublicly(null, $reason)) throw $reason;
+
 		$this->readString('tmpHash');
 	}
 
@@ -337,7 +339,7 @@ class MessageAction extends \wcf\data\AbstractDatabaseObjectAction {
 		foreach ($attachments as $attachment) {
 			$attachmentIDs[] = $attachment->attachmentID;
 		}
-		
+
 		$processor = new \wcf\system\html\input\HtmlInputProcessor();
 		$processor->process(implode(' ', array_map(function ($attachmentID) {
 			return '[attach='.$attachmentID.',none,true][/attach]';
diff --git a/files/style/be.bastelstu.chat.scss b/files/style/be.bastelstu.chat.scss
index d81b96a..32d2176 100644
--- a/files/style/be.bastelstu.chat.scss
+++ b/files/style/be.bastelstu.chat.scss
@@ -4,7 +4,7 @@
  * Use of this software is governed by the Business Source License
  * included in the LICENSE file.
  *
- * Change Date: 2024-11-01
+ * Change Date: 2024-11-02
  *
  * On the date above, in accordance with the Business Source
  * License, use of this software will be governed by version 2
@@ -570,6 +570,11 @@ $chatEmbedMaxWidth: 400px;
 		.attachmentPreview {
 			text-align: center;
 
+			.error {
+				margin-top: 0;
+				margin-bottom: 20px;
+			}
+
 			img {
 				margin-left: auto !important;
 				margin-right: auto !important;
diff --git a/files_wcf/js/Bastelstu.be/Chat/Ui/Attachment/Upload.js b/files_wcf/js/Bastelstu.be/Chat/Ui/Attachment/Upload.js
index 0b7d8ca..cddaa23 100644
--- a/files_wcf/js/Bastelstu.be/Chat/Ui/Attachment/Upload.js
+++ b/files_wcf/js/Bastelstu.be/Chat/Ui/Attachment/Upload.js
@@ -4,7 +4,7 @@
  * Use of this software is governed by the Business Source License
  * included in the LICENSE file.
  *
- * Change Date: 2024-11-01
+ * Change Date: 2024-11-02
  *
  * On the date above, in accordance with the Business Source
  * License, use of this software will be governed by version 2
@@ -177,8 +177,16 @@ define([
 				this.deleteOnClose = false
 				this.closeDialog()
 			} catch (error) {
-				// TODO: Error handling
 				console.error(error)
+
+				let container = this._target.querySelector('.error')
+				if (!container) {
+					container = document.createElement('div')
+					container.classList.add('error')
+					this._target.insertBefore(container, this._target.firstChild)
+				}
+				container.innerText = error.message
+				Dialog.rebuild(DIALOG_CONTAINER_ID)
 			}
 		}