I created a droplet recently (Ubuntu Docker 18.06.1~ce~3 on 18.04).
And I realize emails couldn’t be sent by my application.

I’m using SendGrid’s API.

It works perfectly from my local machine.

I can’t even ping api.sendgrid.com from my droplet.

PING api.sendgrid.com (159.122.219.48) 56(84) bytes of data.
— api.sendgrid.com ping statistics —
328 packets transmitted, 0 received, 100% packet loss, time 335312ms

It works well if I try locally:

$ ping api.sengrid.com
PING api.sengrid.com (85.128.131.76): 56 data bytes
64 bytes from 85.128.131.76: icmpseq=0 ttl=50 time=85.898 ms
64 bytes from 85.128.131.76: icmpseq=1 ttl=50 time=79.936 ms
64 bytes from 85.128.131.76: icmp_seq=2 ttl=50 time=112.295 ms

Why is that endpoint not reachable ?
I tried other endpoints without issues.