Hello,
According to your current description and pictures, it seems that your router connected (was redirected) to operator's private network (without internet access) due to incorrectly used APN. If you have indeed not changed any default router's firewall or routing settings (i.e. if you have not manually experimented with firewall in attempts to block traffic), then your router should be able to acquire internet access once it establishes mobile data connection and if it cannot do so, that would indicate issues within mobile network (e.g. router might not connected to public mobile network)
In this particular situation we would recommend you to contact your SIM provider, inform them about this situation and ask for correct APN which needs to used. Then enter this APN manually in router's "Network -> Mobile" menu.
If issue will persist even with new APN, please ask your mobile operator to investigate from their side why this SIM card cannot access public internet, once connected to their network, since as you already indicated - router successfully established mobile data connection (i.e. done everything it could, and from that moment everything depends on mobile operator network)
