Reconnect a sender whose LinkedIn session broke. `status` is `reconnected`, `checkpoint_required` or `failed`. In every case the sender keeps its id, its campaigns and its seat. For a credentials / infinite-login sender this retries the saved sign-in and runs one attempt now. If its saved provider account no longer exists, a replacement is created from the stored credentials and attached to the same sender. If the person changed their password (or 2FA), pass a new `password` (and `totpSecret`) to replace the stored credentials first. For a `cookie` sender there is no saved password to retry, so pass a fresh `liAt` (and ideally the `userAgent` it came from) to replace the browser session. Without one the call returns 400 `not-supported`. A legacy sender with no stored credentials at all can be repaired by passing `username` + `password`, which converts it into a credentials / infinite-login sender from then on. The alternative for any sender is a hosted connect link scoped to it (POST /accounts/hosted-link with `accountId`), which lets the person sign in themselves. A stored authenticator secret clears a 2FA challenge on its own. Any other challenge comes back as `checkpoint_required` with the `checkpoint` to answer on POST /accounts/{id}/checkpoint.