FlowiseAI/Flowise · warning · Error

User is not a member of this chat

Error message

User is not a member of this chat

What it means

Thrown by RemoveChatMember after it successfully lists the chat's members at GET /chats/{chatId}/members but finds no member whose userId matches the supplied userId. This is a conditional runtime error indicating the user is not currently a participant in the chat, so there is no membership to delete.

Source

Thrown at packages/components/nodes/tools/MicrosoftTeams/core.ts:894

        super({ ...toolInput, accessToken: args.accessToken, defaultParams: args.defaultParams })
    }

    protected async _call(arg: any): Promise<string> {
        const params = { ...arg, ...this.defaultParams }
        const { chatId, userId } = params

        if (!chatId || !userId) {
            throw new Error('Both Chat ID and User ID are required')
        }

        try {
            // First get the membership ID
            const membersEndpoint = `/chats/${chatId}/members`
            const membersResult = await this.makeTeamsRequest(membersEndpoint)

            const member = membersResult.value?.find((m: any) => m.userId === userId)
            if (!member) {
                throw new Error('User is not a member of this chat')
            }

            const endpoint = `/chats/${chatId}/members/${member.id}`
            await this.makeTeamsRequest(endpoint, 'DELETE')

            return this.formatResponse(
                {
                    success: true,
                    message: 'Member removed from chat successfully'
                },
                params
            )
        } catch (error) {
            return this.formatResponse(`Error removing chat member: ${error}`, params)
        }
    }
}

View on GitHub (pinned to abe4a8601a)

Solutions

  1. First call a list-members tool to confirm the user is present before attempting removal.
  2. Treat this error as benign if the goal is just to ensure the user is gone (idempotent removal).
  3. Verify the userId matches the tenant of the chat (same Azure AD object ID format).
  4. Refresh any cached member list before retrying.

Example fix

// before: blind removal
await removeMemberTool._call({ chatId, userId })
// after: check membership first
const members = await listMembersTool._call({ chatId })
const isMember = JSON.parse(members).some(m => m.userId === userId)
if (isMember) await removeMemberTool._call({ chatId, userId })
Defensive patterns

Strategy: validation

Validate before calling

async function isChatMember(listTool: any, chatId: string, userId: string): Promise<boolean> {
  const res = await listTool.call({ chatId })
  const data = JSON.parse(res)
  return Array.isArray(data.value) && data.value.some((m: any) => m.userId === userId)
}

Type guard

null

Try / catch

try {
  await removeMemberTool.call({ chatId, userId })
} catch (e) {
  if (e instanceof Error && e.message === 'User is not a member of this chat') {
    // already removed: treat as success (idempotent)
  } else throw e
}

Prevention

When it happens

Trigger: Calling RemoveChatMember for a user who already left or was never added; using a userId that belongs to a different tenant; the chat membership list is stale because the user was removed by another process; case/format mismatch between the supplied userId and the userId field returned by Graph.

Common situations: Idempotency issue: an agent retries a removal that already succeeded; cross-tenant confusion where a userId from tenant A is used against a chat in tenant B; the agent picked a stale userId from a cached member list.

Related errors

AI-assisted analysis of FlowiseAI/Flowise@abe4a8601a (2026-08-12). Data as JSON: /api/errors/65f4ab220e4c0be2. Report an issue: GitHub.