diff --git a/mautrix_telegram/bot.py b/mautrix_telegram/bot.py
index 1dee6ca7..7c4f1e0c 100644
--- a/mautrix_telegram/bot.py
+++ b/mautrix_telegram/bot.py
@@ -29,6 +29,7 @@ from telethon.tl.types import (
     ChatForbidden,
     ChatParticipantAdmin,
     ChatParticipantCreator,
+    ChatParticipantsForbidden,
     InputChannel,
     InputUser,
     MessageActionChatAddUser,
@@ -198,6 +199,8 @@ class Bot(AbstractUser):
             return pcp
         elif isinstance(chat, PeerChat):
             chat = await self.client(GetFullChatRequest(chat.chat_id))
+            if isinstance(chat.full_chat.participants, ChatParticipantsForbidden):
+                return None
             participants = chat.full_chat.participants.participants
             for p in participants:
                 self._admin_cache[chat.channel_id, tgid] = (p, time.time())
diff --git a/mautrix_telegram/portal_util/participants.py b/mautrix_telegram/portal_util/participants.py
index eaa29ff6..c5f0d543 100644
--- a/mautrix_telegram/portal_util/participants.py
+++ b/mautrix_telegram/portal_util/participants.py
@@ -24,6 +24,7 @@ from telethon.tl.types import (
     ChannelParticipantBanned,
     ChannelParticipantsRecent,
     ChannelParticipantsSearch,
+    ChatParticipantsForbidden,
     InputChannel,
     InputUser,
     TypeChannelParticipant,
@@ -93,6 +94,8 @@ async def get_users(
 ) -> list[TypeUser]:
     if peer_type == "chat":
         chat = await client(GetFullChatRequest(chat_id=tgid))
+        if isinstance(chat.full_chat.participants, ChatParticipantsForbidden):
+            return []
         users = list(_filter_participants(chat.users, chat.full_chat.participants.participants))
         return users[:limit] if limit > 0 else users
     elif peer_type == "channel":