Connect to Cloud SQL using IP

I want to connect to a Google Cloud SQL instance using IP (not from another google service like appengine). To connect I'm using phpMyAdmin and MySql, both cannot connect.

CloudSql Instance details

Instance type: MySQL First Generation tier: D1
Version: MySQL 5.5
Authorized network: ::/0 (everybody based on documentation)
Authorized user: a user with no password and allowed from any domain (%)

Connecting client specs

phpMyAdmin 4.6.4 (fresh install)
MySQL Version 5.5.52-cll

So I have an instance that can be connected from everywhere but still cannot connect.

MySql using ssh

mysql --host=the:ipv6:of:the:instance --user=theusername --password

and I get an error

ERROR 2003 (HY000): Can't connect to MySQL server on 'the:ipv6:of:the:instance' (110)

PhpMyAdmin config.inc.php

$cfg['Servers'][$i]['host'] = 'the:ipv6:of:the:instance';
$cfg['Servers'][$i]['connect_type'] = 'tcp';
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['AllowNoPassword'] = true;
$cfg['Servers'][$i]['auth_type'] = 'cookie';
$cfg['blowfish_secret'] = 'some secret';

The error here is: #2003 - Can't connect to MySQL server on 'the:ipv6:of:the:instance' (110) — The server is not responding.

Verifying ipv6

Since I'm connecting using ipv6, I had to verify that I'm not hallucinating and I am indeed connecting from an ipv6 client.

The phpMyAdmin was run from http://[my:own:ipv6:address]/index.php so no doubt that I was indeed using ipv6

[edit] As suggested by @David I ran ping6 www.google.com from the client and worked, also checked that the client can be accessed using its ipv6 by pinging it from another computer (from windows: ping -6 my:own:ipv6:address)

References

Other things I tried

Another user: root, a user with password
To another new cloud sql instance
Checked the console log viewer, nothing interesting
Veryfied that there is an AAAA for my ipv6 on the domain I am requesting from, that ip resolves and my dns works perfectly
I am not behind a proxy

Any help would be greatly appreciated to either connect or at least debug what is going on. I want to clarify that I don't consider myself above novice in network-related stuff.

Solution

Given that the two different cases have different errors, they are clearly different issues.

Command Line issue

You may not have IPv6 connectivity on the host you are SSHing to - for example GCE does not. To test this try running ping6 www.google.com. You may also have an outbound firewall on port 3306.

PHPMyAdmin issue

You should be using $cfg['Servers'][$i]['host'] instead of $cfg['Servers'][$i]['socket']. You will also need to set a password and possibly a username too. You should not be running Cloud SQL with no password required.