Cisco packet tracer is a simulator. When you increment the complexity of the topology, then, the probability of bugs can increase or the pings can delay in operate correctly.
You must try with ping and can see some packets are not successful but after of some failure packets, you could see the connectivity
It is the same case
Your configurations are ok
Thank you for you reply.
First time i am configuring wrong way specially on distribution of static and default routes to OSPF. Maybe your right.
I am interested in how to provide such type of network which has 2 core routers and 2 core switches.
Which one of these topology is good design.
How to make it good design?