RocketChat/Rocket.Chat · error

User not found

Error message

User not found

What it means

Users.findOneByUsernameIgnoringCase(data.username) found no user, so the ban target does not exist. Username (not user id or display name) is the lookup key and must match a current username case-insensitively.

Source

Thrown at apps/meteor/server/lib/banUserFromRoom.ts:33

	const room = await Rooms.findOneById(data.rid);

	if (!room || !(await roomCoordinator.getRoomDirectives(room.t).allowMemberAction(room, RoomMemberActions.BAN, fromId))) {
		throw new Error('Not allowed');
	}

	const fromUser = await Users.findOneById(fromId);
	if (!fromUser) {
		throw new Error('Invalid user');
	}

	if (!(await canAccessRoomAsync(room, fromUser))) {
		throw new Error('The required "roomId" or "roomName" param provided does not match any group');
	}

	const bannedUser = await Users.findOneByUsernameIgnoringCase(data.username);
	if (!bannedUser) {
		throw new Error('User not found');
	}

	const subscription = await Subscriptions.findOneByRoomIdAndUserId(data.rid, bannedUser._id, {
		projection: { _id: 1, status: 1 },
	});
	if (!subscription) {
		throw new Error('User is not in this room');
	}

	// Cannot ban a user who is already banned
	if (isBannedSubscription(subscription)) {
		throw new Error('User is already banned from this room');
	}

	// Cannot ban the last owner
	if (await hasRoleAsync(bannedUser._id, 'owner', room._id)) {
		const numOwners = await Roles.countUsersInRole('owner', room._id);

View on GitHub (pinned to b2c16d5842)

Solutions

1. Resolve the user first (users.info?username=...) and submit the canonical username
2. Offer username autocomplete instead of free-text entry
3. Handle 'User not found' distinctly from 'Not allowed' in the UI

const { user } = await GET '/api/v1/users.info' { username };
if (!user) {
  // no such username - do not call rooms.banUser
}

try {
  await POST '/api/v1/rooms.banUser' { roomId, username };
} catch (e) {
  if (String(e.message).includes('User not found')) {
    // resolve canonical username via users.info and retry once
  } else {
    throw e;
  }
}

When it happens

Trigger: Typo in the username payload; the target renamed their username; a deleted or deactivated user; passing the display name or user id where username is expected.

Common situations: Hand-typed /ban slash commands; bots guessing usernames; UIs submitting stale usernames from an old member list.

Related errors

• Not allowed
• Invalid user
• The required "roomId" or "roomName" param provided does not
• User is not in this room
• User is already banned from this room

AI-assisted analysis of RocketChat/Rocket.Chat@b2c16d5842 (2026-08-18). Data as JSON: /api/errors/517e0346c25062d5. Report an issue: GitHub.