Security

Hi guys, first time posting here, so let me start by thanking for being a great community and helping me multiple times while sitting in the shadows :D

My internet was delivered and informed to configure it with C-VLAN:301 and S-VLAN:504, so I've configured this on my SRX380:

flexible-vlan-tagging;
unit 301 {
    vlan-tags outer 504 inner 301;
    family inet {
        address 100.2.100.126/30;
    }
}

Unfortunately I am still not able to ping the PE/ISP with this configuration. Am I missing something  obvious?

try adding 

set interfaces ge-0/0/0 vlan-stacking

also do you have security policies and zones setup?

Does your ISP expect the TPID, some use 0x88a8 for the S-Tag, if they do you need to add

set interfaces ge-0/0/0 gigether-options ethernet-switch-profile tag-protocol-id 0x88a8