Wait until `bitcoind` has synchronized with the testnet network. In case you use regtest, make sure you generate at least 432 blocks to activate SegWit.
Make sure that you do not have `walletbroadcast=0` in your
`~/.bitcoin/bitcoin.conf`, or you may run into trouble.
`~/.bitcoin/bitcoin.conf`, or you may run into trouble. Notice that
currently pruned nodes are not supported and may result in
`lightningd` being unable to synchronize with the blockchain.
You can start `lightningd` with the following command: