You are adding a WhatsApp number and it is refused: a channel already exists for this phone number.
The refusal is exactly true and it is wider than your workspace. A WhatsApp number can be connected once across the whole installation, not once per account. So the number may be in use somewhere you cannot see.
Why it works that way
Incoming messages are delivered per number. If two inboxes claimed the same number, there would be no honest answer to the question of which conversation an arriving message belongs to. The uniqueness is what keeps that from happening.
What to do
If it is your own number, in your own workspace. Look for it in Settings → Inboxes — including inboxes you may have archived or forgotten. If it is there and broken, you want reconnect a WhatsApp number, not a second inbox.
If you cannot find it. Then it is connected in another workspace on this installation. Only the operator can see that, so this is a support request: give them the number and ask where it is connected. They can see it; you cannot, and that is deliberate.
If it was connected by a colleague who has left. Same answer. The inbox still exists and still owns the number; it needs to be found and either handed over or removed.
What not to do
Do not try the number in a different format, with or without a leading +, or with the country code written
differently. The check is on the number, and working around it is not possible — the attempts only add noise to
whatever the operator has to read later.
Who can do this
Administrators add inboxes. Finding a number connected in another workspace needs the operator of the installation.
Limits
- Lynomia Chat will not tell you which account holds the number. Naming another workspace to you would leak it; the refusal is deliberately plain.
- Removing the other inbox is not something you can do unless it is in your own account.
- Deleting an inbox to free a number can release the number from the Meta app, which is a second problem. Reconnecting is almost always what you actually want.