bitcoind (JSON-RPC) returned HTTP 403 error, i don't know why I set up bitcoind in Ubuntu 14.04 and I requested "getinfo", 
but returned HTTP 403 error "FORBIDDEN". I don't know why...

The environment is below..
・Ubuntu is installed in Virtualbox and bitcoind is installed in the Ubuntu.
・The Host OS is Mac OS.
・The Host OS and the gest OS (Ubuntu) is connected host only adapter.
  (Host OS -> 10.0.2.2  Gest OS-> 192.168.33.33)

The bitcoin.conf is below


  server=1
  
  daemon=1
  
  rpcallowip = 10.0.2.0/24
  
  rpcuser=...
  
  rpcpassword=...
  
  rpcport=8332
  
  txindex=1
  
  keypool=100


From the browser, type "http://rpcuser:rpcpassword@192.168.33.33:8332/"
but it gives "Forbidden"

Forthermore, i tried to use easybitcoin.php (https://github.com/aceat64/EasyBitcoin-PHP/blob/master/easybitcoin.php),
but also the same like "HTTP_FORBIDDEN" "403"

Can you give me any advices?
Your rpcallowip setting is 10.0.2.0, but you listed 10.0.2.2 as the host OS's IP. That could be your issue.