Bcoin - Database backend not found /root/BCoin/node_modules/bcoin/lib/db/backends.js:16
    throw new Error('Database backend "' + name + '" not found.');
    ^

Error: Database backend "leveldown" not found.
    at Object.get (/root/BCoin/node_modules/bcoin/lib/db/backends.js:16:11)
    at Function.getTarget (/root/BCoin/node_modules/bcoin/lib/db/ldb.js:118:21)
    at LDB (/root/BCoin/node_modules/bcoin/lib/db/ldb.js:32:20)
    at new ChainDB (/root/BCoin/node_modules/bcoin/lib/blockchain/chaindb.js:58:13)
    at new Chain (/root/BCoin/node_modules/bcoin/lib/blockchain/chain.js:91:13)
    at Object.&lt;anonymous&gt; (/root/BCoin/p2p_pool.js:7:13)
    at Module._compile (module.js:569:30)
    at Object.Module._extensions..js (module.js:580:10)
    at Module.load (module.js:503:32)
    at tryModuleLoad (module.js:466:12)
root@NoobEngine1:~/BCoin#
This happens when your dependencies get twisted up, especially when bcoin has an update where leveldown gets upgraded. You should be good with a npm rebuild leveldown to fix the dependency tree, but if that doesn't work rm -rf node_modules &amp;&amp; npm i