Fix CGNAT on 4G Router

My 4G LTE router sits behind carrier-grade NAT and external access has become unreliable. I need you to dive into the current configuration, pinpoint what CGNAT-related settings (APN, PDP context, NAT, port-forward, DMZ, IPv6 passthrough, etc.) are blocking or throttling traffic, and apply corrective tweaks so that inbound and outbound connectivity is stable again.

You’ll receive:
• remote access to the router’s UI (and SSH if needed)
• a brief log of the symptoms I can reproduce

What I need back from you is a concise, step-by-step record of the troubleshooting you perform, the configuration changes you make (or recommend) and a final validation that devices on my LAN can once again reach and be reached through CGNAT without drops or slow-downs. If firmware or APN profile upgrades are required, document the exact versions and links.

Tools you are likely to touch: MikroTik RouterOS / OpenWRT CLI, LTE modem AT-commands, Wireshark or similar packet captures, and standard IPv4/IPv6 diagnostics (traceroute, ping, iperf). As soon as the link is fully restored and your report is delivered, the job is complete.