CodeIgniter 3.1.5 On Ubuntu 16.04 and few issues

I tested to have CI 3.15 code based project on Ubuntu 16.04.  The strange error is it can not find the CURL extension
when I actually already had it enabled on server.  Anyone has same problem and how you solve it , I appreciate it!

Here are the system config on mine:

PHP 7.1.8-2+ubuntu16.04.1+deb.sury.org+4 (cli) (built: Aug  4 2017 13:04:12) ( NTS )
Copyright © 1997-2017 The PHP Group
Zend Engine v3.1.0, Copyright © 1998-2017 Zend Technologies
    with Zend OPcache v7.1.8-2+ubuntu16.04.1+deb.sury.org+4, Copyright © 1999-2017, by Zend Technologies

and the curl curl 7.49.0 (x86_64-pc-linux-gnu) libcurl/7.49.0
Protocols: dict file ftp gopher http imap pop3 rtsp smtp telnet tftp 
Features: Largefile UnixSockets 

Regards