Explorer config:
{
"network-config": {
    "org1": {
        "name": "hlfv1",
        "mspid": "Org1MSP",
        "peer1": {
            "requests": "grpc://localhost:7050",
            "events": "grpc://localhost:7053",
            "server-hostname": "peer0.org1.example.com"
        },
        "admin": {
            "key": "../fabric-tools/fabric-scripts/hlfv1/composer/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/keystore",
            "cert": "../fabric-tools/fabric-scripts/hlfv1/composer/crypto-config/peerOrganizations/org1.example.com/users/Admin@org1.example.com/msp/signcerts"
        }
    }
},
"host": "localhost",
"port": "5000",
"channel": "composerchannel",
"keyValueStore": "/tmp/fabric-client-kvs",
"eventWaitTime": "30000",
"mysql":{
    "host":"127.0.0.1",
    "database":"fabricexplorer",
    "username":"root",
    "passwd":"******"
}
Error:
[client-utils.js]: sendPeersProposal - Promise is rejected: Error: 12 UNIMPLEMENTED: unknown service protos.Endorser
    at new createStatusError (/blockchain-explorer/node_modules/grpc/src/client.js:65:15)
    at /blockchain-explorer/node_modules/grpc/src/client.js:568:15
[Channel.js]: Failed Query channel info. Error: Error: 12 UNIMPLEMENTED: unknown service protos.Endorser
    at new createStatusError (/blockchain-explorer/node_modules/grpc/src/client.js:65:15)
    at /blockchain-explorer/node_modules/grpc/src/client.js:568:15
[ERROR] Query - [39mError: 12 UNIMPLEMENTED: unknown service protos.Endorser
    at new createStatusError (/blockchain-explorer/node_modules/grpc/src/client.js:65:15)
    at /blockchain-explorer/node_modules/grpc/src/client.js:568:15
[31m[2018-02-08 13:54:07.217] [ERROR] blockscanner -[39mTypeError: Cannot read property 'low' of undefined
    at getChainInfo.then.response (/blockchain-explorer/app/query.js:208:33)
    at <anonymous> ....