Node unreachable, port 8333 opened

Port 8333 opened, bitcoin-cli showing inbound connections:

Code:

[bitcoin@server bitcoin]# /home/bitcoin/bitcoin-cli -datadir=/home/bitcoin -conf=/home/bitcoin/bitcoin.conf getpeerinfo | grep inbound
   "inbound": false,
   "inbound": false,
   "inbound": false,
   "inbound": false,
   "inbound": false,
   "inbound": false,
   "inbound": true,
   "inbound": false,
   "inbound": false,
   "inbound": true,
   "inbound": true,
   "inbound": true,

Fully sync'd:

Code:

{
  "version": 140100,
  "protocolversion": 70015,
  "walletversion": 60000,
  "balance": 0.00000000,
  "blocks": 467593,
  "timeoffset": 0,
  "connections": 14,
  "proxy": "",
  "difficulty": 559970892890.8381,
  "testnet": false,
  "keypoololdest": 1489099117,
  "keypoolsize": 100,
  "paytxfee": 0.00000000,
  "relayfee": 0.00001000,
  "errors": ""
}

Bitnodes.21.co test is failing with "node unreachable".

Port is opened, I can cURL to port 8333 from outside networks.

Code:

curl -v x.x.x.x:8333
* Rebuilt URL to: x.x.x.x:8333/
* Trying x.x.x.x...
* TCP_NODELAY set
* Connected to x.x.x.x (x.x.x.x) port 8333 (#0)
> GET / HTTP/1.1
> Host: x.x.x.x:8333
> User-Agent: curl/7.51.0
> Accept: */*
>
* Curl_http_done: called premature == 0
* Empty reply from server
* Connection #0 to host x.x.x.x left intact
curl: (52) Empty reply from server

Any suggestions?