Unable to update composer - connection timeout error

I am able to ssh into my droplet. Am also able to apt update and apt upgrade.
When I try to run sudo composer self-update or composer update, I am getting connection timeout error.

The "https://getcomposer.org/versions" file could not be downloaded: failed to open stream: Connection timed out  

output of ufw status

To                         Action      From

output of composer diagnose

Checking platform settings: OK
Checking git settings: OK
Checking http connectivity to packagist: FAIL
[Composer\Downloader\TransportException] The "http://packagist.org/packages.json" file    could not be downloaded: failed to open stream: Connection timed out
Checking https connectivity to packagist: FAIL
[Composer\Downloader\TransportException] The "https://packagist.org/packages.json" file    could not be downloaded: failed to open stream: Connection timed out
Checking github.com rate limit: OK
Checking disk free space: OK
Checking composer version: 

                                                                           
  [Composer\Downloader\TransportException]                                     
  The "https://getcomposer.org/version" file could not be downloaded: failed   
  to open stream: Connection timed out

output of composer --version

Composer version 1.0-dev (9e9c1917e1ed9f3f78b195a785aee3c6dc3cb883) 2015-11-23 10:31:23  

output of curl IL http://packagist.org/packages.json

HTTP/1.1 200 OK
Server: nginx
Date: Sun, 10 Dec 2017 08:40:20 GMT
Content-Type: application/json
Content-Length: 1302
Last-Modified: Sun, 10 Dec 2017 08:38:28 GMT
Connection: keep-alive
ETag: "5a2cf284-516"
Cache-Control: private, max-age=0, no-cache
Accept-Ranges: bytes  

I tried to manually get a copy of latest composer but it also doesn’t work
output of php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"

PHP Warning:  copy(https://getcomposer.org/installer): failed to open stream: Connection timed out in Command line code on line 1  

What could be the reason? I was all working till about a week ago. I am able to visit (browse) the webpages hosted on my droplet.