This is my ufw status; Yes, the 3306 Mysql is allowed
$ ufw status
Status: active
To Action From
-- ------ ----
Nginx Full ALLOW Anywhere
OpenSSH ALLOW Anywhere
3000/tcp ALLOW Anywhere
3306/tcp ALLOW Anywhere
1337/tcp ALLOW Anywhere
Nginx Full (v6) ALLOW Anywhere (v6)
OpenSSH (v6) ALLOW Anywhere (v6)
3000/tcp (v6) ALLOW Anywhere (v6)
3306/tcp (v6) ALLOW Anywhere (v6)
1337/tcp (v6) ALLOW Anywhere (v6)