Are you using the agora.download or test.agora.download? If you're using test.agora.download, are you paying with htlc.me? Can you provide the invoice ID? (It's the hexadecimal string after `/invoice/`.)
If you're using htlc.me, that's probably the issue. htlc.me is a testnet wallet, so it can only pay testnet invoices, and agora.download is on mainnet.
