Hi @atulsharma Sir/All,
I am unable to add Chandigarh “3rd Router” with Mumbai “Middle Router”.
Router is successfully connected with 2 Routers and 1 switch but I am unable to connect 3rd Router with it.
Getting error: “The cable cannot be connected to that port” PFB the screenshot of the topology. Kindly help on priority.
Hi Prateek, Please add one extra module of NIM-ES2-4 on the Mumbai router and then connect the switch to it.
Hi Parag, thanks a lot!
This was really helpful. Now connected the Chandigarh router to Mumbai. 
Port Ge 0/0/0 has two ports Fiber and UTP in the same module that’s why we can connect only three cables and not 4 cables.
Also when you type show ip interface brief we will be able to see only 3 ports and not four.
Updated Remarks for audience:
As Router ISR4331 is used in this topology, it has a limitation of adding only 3 Router/Switch with it.
4th Router can be connected through the Serial Port.
We need to add Module:- “NIM-2T” in both routers. i.e. Chandigarh & Mumbai to connect them through the serial cable.
Thanks!
