If you are using a lightning network when sending BTC the receiver must be also connected to the lightning network if not the receiver won't able to generate an invoice or address of his LN wallet.
Unless the sender trying to send BTC via LN to Bitcoin address? It won't work, the LN address is a long text and the sender should request an invoice from the receiver before the sender can able to send BTC.
You might not yet understand how the lightning network works. I suggest check this big list below about lightning networks.
-
https://bitcointalk.org/index.php?topic=5345664.