diff --git a/zerver/lib/message.py b/zerver/lib/message.py
index b873e310ec..5b37f745d4 100644
--- a/zerver/lib/message.py
+++ b/zerver/lib/message.py
@@ -1220,21 +1220,23 @@ def check_user_group_mention_allowed(sender: UserProfile, user_group_ids: List[i
 
     for group in user_groups:
         can_mention_group = group.can_mention_group
-        can_mention_group_name = can_mention_group.named_user_group.name
         if sender_is_system_bot:
-            if can_mention_group_name == SystemGroups.EVERYONE:
+            if (
+                hasattr(can_mention_group, "named_user_group")
+                and can_mention_group.named_user_group.name == SystemGroups.EVERYONE
+            ):
                 continue
             raise JsonableError(
-                _(
-                    "You are not allowed to mention user group '{user_group_name}'. You must be a member of '{can_mention_group_name}' to mention this group."
-                ).format(user_group_name=group.name, can_mention_group_name=can_mention_group_name)
+                _("You are not allowed to mention user group '{user_group_name}'.").format(
+                    user_group_name=group.name
+                )
             )
 
         if not is_user_in_group(can_mention_group, sender, direct_member_only=False):
             raise JsonableError(
-                _(
-                    "You are not allowed to mention user group '{user_group_name}'. You must be a member of '{can_mention_group_name}' to mention this group."
-                ).format(user_group_name=group.name, can_mention_group_name=can_mention_group_name)
+                _("You are not allowed to mention user group '{user_group_name}'.").format(
+                    user_group_name=group.name
+                )
             )
 
 
diff --git a/zerver/tests/test_message_edit.py b/zerver/tests/test_message_edit.py
index c8d3d2e1d9..494e53ceed 100644
--- a/zerver/tests/test_message_edit.py
+++ b/zerver/tests/test_message_edit.py
@@ -17,7 +17,7 @@ from zerver.lib.test_classes import ZulipTestCase
 from zerver.lib.test_helpers import queries_captured
 from zerver.lib.topic import TOPIC_NAME
 from zerver.lib.utils import assert_is_not_none
-from zerver.models import Message, NamedUserGroup, Realm, UserProfile, UserTopic
+from zerver.models import Message, NamedUserGroup, Realm, UserGroup, UserProfile, UserTopic
 from zerver.models.groups import SystemGroups
 from zerver.models.realms import get_realm
 from zerver.models.streams import get_stream
@@ -1487,7 +1487,7 @@ class EditMessageTest(ZulipTestCase):
         )
         self.assert_json_error(
             result,
-            f"You are not allowed to mention user group '{leadership.name}'. You must be a member of '{moderators_system_group.name}' to mention this group.",
+            f"You are not allowed to mention user group '{leadership.name}'.",
         )
 
         # The restriction does not apply on silent mention.
@@ -1536,7 +1536,7 @@ class EditMessageTest(ZulipTestCase):
         )
         self.assert_json_error(
             result,
-            f"You are not allowed to mention user group '{support.name}'. You must be a member of '{leadership.name}' to mention this group.",
+            f"You are not allowed to mention user group '{support.name}'.",
         )
 
         msg_id = self.send_stream_message(othello, "test_stream", "Test message")
@@ -1571,7 +1571,7 @@ class EditMessageTest(ZulipTestCase):
         )
         self.assert_json_error(
             result,
-            f"You are not allowed to mention user group '{support.name}'. You must be a member of '{leadership.name}' to mention this group.",
+            f"You are not allowed to mention user group '{support.name}'.",
         )
 
         msg_id = self.send_stream_message(othello, "test_stream", "Test message")
@@ -1584,7 +1584,7 @@ class EditMessageTest(ZulipTestCase):
         )
         self.assert_json_error(
             result,
-            f"You are not allowed to mention user group '{leadership.name}'. You must be a member of '{moderators_system_group.name}' to mention this group.",
+            f"You are not allowed to mention user group '{leadership.name}'.",
         )
 
         msg_id = self.send_stream_message(shiva, "test_stream", "Test message")
@@ -1596,3 +1596,62 @@ class EditMessageTest(ZulipTestCase):
             },
         )
         self.assert_json_success(result)
+
+        # Test all the cases when can_mention_group is not a named user group.
+        content = "Test mentioning user group @*leadership*"
+        user_group = UserGroup.objects.create(realm=iago.realm)
+        user_group.direct_members.set([othello])
+        user_group.direct_subgroups.set([moderators_system_group])
+        leadership.can_mention_group = user_group
+        leadership.save()
+
+        msg_id = self.send_stream_message(othello, "test_stream", "Test message")
+        self.login("othello")
+        result = self.client_patch(
+            "/json/messages/" + str(msg_id),
+            {
+                "content": content,
+            },
+        )
+        self.assert_json_success(result)
+
+        msg_id = self.send_stream_message(shiva, "test_stream", "Test message")
+        self.login("shiva")
+        result = self.client_patch(
+            "/json/messages/" + str(msg_id),
+            {
+                "content": content,
+            },
+        )
+        self.assert_json_success(result)
+
+        msg_id = self.send_stream_message(iago, "test_stream", "Test message")
+        self.login("iago")
+        result = self.client_patch(
+            "/json/messages/" + str(msg_id),
+            {
+                "content": content,
+            },
+        )
+        self.assert_json_success(result)
+
+        msg_id = self.send_stream_message(cordelia, "test_stream", "Test message")
+        self.login("cordelia")
+        result = self.client_patch(
+            "/json/messages/" + str(msg_id),
+            {
+                "content": content,
+            },
+        )
+        self.assert_json_error(
+            result, f"You are not allowed to mention user group '{leadership.name}'."
+        )
+
+        content = "Test mentioning user group @_*leadership*"
+        result = self.client_patch(
+            "/json/messages/" + str(msg_id),
+            {
+                "content": content,
+            },
+        )
+        self.assert_json_success(result)
diff --git a/zerver/tests/test_message_send.py b/zerver/tests/test_message_send.py
index 71a9685e6c..31656986e2 100644
--- a/zerver/tests/test_message_send.py
+++ b/zerver/tests/test_message_send.py
@@ -55,6 +55,7 @@ from zerver.models import (
     Recipient,
     Stream,
     Subscription,
+    UserGroup,
     UserMessage,
     UserProfile,
 )
@@ -2129,7 +2130,7 @@ class StreamMessagesTest(ZulipTestCase):
         leadership.save()
         with self.assertRaisesRegex(
             JsonableError,
-            f"You are not allowed to mention user group '{leadership.name}'. You must be a member of '{moderators_system_group.name}' to mention this group.",
+            f"You are not allowed to mention user group '{leadership.name}'.",
         ):
             self.send_stream_message(cordelia, "test_stream", content)
 
@@ -2156,7 +2157,7 @@ class StreamMessagesTest(ZulipTestCase):
         content = "Test mentioning user group @*support*"
         with self.assertRaisesRegex(
             JsonableError,
-            f"You are not allowed to mention user group '{support.name}'. You must be a member of '{leadership.name}' to mention this group.",
+            f"You are not allowed to mention user group '{support.name}'.",
         ):
             self.send_stream_message(iago, "test_stream", content)
 
@@ -2171,13 +2172,13 @@ class StreamMessagesTest(ZulipTestCase):
         content = "Test mentioning user group @*support* @*leadership*"
         with self.assertRaisesRegex(
             JsonableError,
-            f"You are not allowed to mention user group '{support.name}'. You must be a member of '{leadership.name}' to mention this group.",
+            f"You are not allowed to mention user group '{support.name}'.",
         ):
             self.send_stream_message(iago, "test_stream", content)
 
         with self.assertRaisesRegex(
             JsonableError,
-            f"You are not allowed to mention user group '{leadership.name}'. You must be a member of '{moderators_system_group.name}' to mention this group.",
+            f"You are not allowed to mention user group '{leadership.name}'.",
         ):
             self.send_stream_message(othello, "test_stream", content)
 
@@ -2197,7 +2198,7 @@ class StreamMessagesTest(ZulipTestCase):
         system_bot = get_system_bot(settings.EMAIL_GATEWAY_BOT, internal_realm.id)
         with self.assertRaisesRegex(
             JsonableError,
-            f"You are not allowed to mention user group '{support.name}'. You must be a member of '{members_group.name}' to mention this group.",
+            f"You are not allowed to mention user group '{support.name}'.",
         ):
             self.send_stream_message(system_bot, "test_stream", content, recipient_realm=iago.realm)
 
@@ -2213,6 +2214,43 @@ class StreamMessagesTest(ZulipTestCase):
         result = self.api_get(shiva, "/api/v1/messages/" + str(msg_id))
         self.assert_json_success(result)
 
+        # Test all the cases when can_mention_group is not a named user group.
+        content = "Test mentioning user group @*leadership*"
+        user_group = UserGroup.objects.create(realm=iago.realm)
+        user_group.direct_members.set([othello])
+        user_group.direct_subgroups.set([moderators_system_group])
+        leadership.can_mention_group = user_group
+        leadership.save()
+
+        msg_id = self.send_stream_message(othello, "test_stream", content)
+        result = self.api_get(cordelia, "/api/v1/messages/" + str(msg_id))
+        self.assert_json_success(result)
+
+        msg_id = self.send_stream_message(shiva, "test_stream", content)
+        result = self.api_get(cordelia, "/api/v1/messages/" + str(msg_id))
+        self.assert_json_success(result)
+
+        msg_id = self.send_stream_message(iago, "test_stream", content)
+        result = self.api_get(cordelia, "/api/v1/messages/" + str(msg_id))
+        self.assert_json_success(result)
+
+        with self.assertRaisesRegex(
+            JsonableError,
+            f"You are not allowed to mention user group '{leadership.name}'.",
+        ):
+            self.send_stream_message(cordelia, "test_stream", content)
+
+        with self.assertRaisesRegex(
+            JsonableError,
+            f"You are not allowed to mention user group '{leadership.name}'.",
+        ):
+            self.send_stream_message(system_bot, "test_stream", content, recipient_realm=iago.realm)
+
+        content = "Test mentioning user group @_*leadership*"
+        msg_id = self.send_stream_message(shiva, "test_stream", content)
+        result = self.api_get(cordelia, "/api/v1/messages/" + str(msg_id))
+        self.assert_json_success(result)
+
     def test_stream_message_mirroring(self) -> None:
         user = self.mit_user("starnine")
         self.subscribe(user, "Verona")