The success check only grepped "message" from the response body, but
PVE/PBS auth failures return HTTP 401 with an empty body, so wrong or
unauthorized API tokens were reported as "Certificate successfully
deployed". Also _retval captured the exit code of the message pipeline
instead of _post. Check the HTTP status line from $HTTP_HEADER and
capture _post's exit code directly.
fix https://github.com/acmesh-official/acme.sh/issues/7141