diff --git a/src/channels/chat-sdk-bridge.ts b/src/channels/chat-sdk-bridge.ts
index 5cbf0c6..df3e305 100644
--- a/src/channels/chat-sdk-bridge.ts
+++ b/src/channels/chat-sdk-bridge.ts
@@ -14,10 +14,12 @@ import {
   Button,
   Modal,
   TextInput,
+  markdownToPlainText,
   type Adapter,
   type ConcurrencyStrategy,
   type Message as ChatMessage,
 } from 'chat';
+import { ValidationError } from '@chat-adapter/shared';
 import { log } from '../log.js';
 import { SqliteStateAdapter } from '../state-sqlite.js';
 import type { ChannelAdapter, ChannelSetup, ConversationConfig, InboundMessage } from './adapter.js';
@@ -373,12 +375,30 @@ export function createChatSdkBridge(config: ChatSdkBridgeConfig): ChannelAdapter
           data: f.data,
           filename: f.filename,
         }));
-        if (fileUploads && fileUploads.length > 0) {
-          const result = await adapter.postMessage(tid, { markdown: text, files: fileUploads });
-          return result?.id;
-        } else {
-          const result = await adapter.postMessage(tid, { markdown: text });
-          return result?.id;
+        try {
+          if (fileUploads && fileUploads.length > 0) {
+            const result = await adapter.postMessage(tid, { markdown: text, files: fileUploads });
+            return result?.id;
+          } else {
+            const result = await adapter.postMessage(tid, { markdown: text });
+            return result?.id;
+          }
+        } catch (err) {
+          // Permanent formatting failure (e.g. Telegram MarkdownV2 entity parse error):
+          // retry once as plain text so the queue isn't blocked forever.
+          if (err instanceof ValidationError) {
+            log.warn('Markdown rejected by adapter, retrying as plain text', {
+              adapter: adapter.name,
+              err: err.message,
+            });
+            const plain = markdownToPlainText(text);
+            const result = await adapter.postMessage(tid, plain);
+            if (fileUploads && fileUploads.length > 0) {
+              await adapter.postMessage(tid, { markdown: '', files: fileUploads });
+            }
+            return result?.id;
+          }
+          throw err;
         }
       } else if (message.files && message.files.length > 0) {
         // Files only, no text