sandbox_account_limit

Your sandbox already holds its maximum number of accounts (5 by default).

HTTP 403. Nothing reached the broker.

Likely cause: Creating a sixth account with a sandbox (twsk_) key.

What to do: Delete a sandbox account you no longer need, then create the new one.

Retry: No. The same request gets the same answer; change something first.

Listed under Sandbox in Errors. Send the error’s requestId to support and we can find the request.