OSPF

[shammasnawaz]

Dear Cisco Team,

we are getting this logs on my cisco router, I have two core switches core 1 and core 2 and my router is connected to directly connected to core 2 and 2nd cable of router is going to HUB and core1 is connected via Hub.

ERROR:

*Dec 27 04:54:04.136: %OSPF-5-ADJCHG: Process 100, Nbr 10.10.50.1 on GigabitEthernet0/1.100 from FULL to DOWN, Neighbor Down: Dead timer expired
*Dec 27 04:54:07.692: %OSPF-5-ADJCHG: Process 100, Nbr 10.10.50.2 on GigabitEthernet0/1.100 from FULL to DOWN, Neighbor Down: Dead timer expired
*Dec 27 04:54:20.728: %OSPF-5-ADJCHG: Process 100, Nbr 10.10.50.1 on GigabitEthernet0/1.100 from LOADING to FULL, Loading Done
*Dec 27 04:54:22.116: %OSPF-5-ADJCHG: Process 100, Nbr 10.10.50.2 on GigabitEthernet0/1.100 from LOADING to FULL, Loading Done
*Dec 27 04:55:12.308: %OSPF-5-ADJCHG: Process 100, Nbr 10.10.50.1 on GigabitEthernet0/1.100 from LOADING to FULL, Loading Done

NOTE:

10.10.50.1 THIS IP is loop back IP of my core 1 and 10.10.50.2 this one is loop back ip of my core2 please help me why i received logs on my router, When received this logs due to this packets drops from internet and also packet drops from LAN to Router.

Thank You.

[MHM Cisco World]

what is network type you use P2P? If yes, then change it to P2M in Hub. 
other option is config broadcast but you must sure that the Hub must be the DR of broadcast domain.

[balaji.bandi]

Can you post the topology some config bits to understand the issue.

as per the logs we know that OSPF flapping ( when ? frequently ?) - is this worked before? what was the change?

as suggested - depends on the DMVPN config- if this is Phase 3 I would suggest using point-to-Multipoint. if Phase 2 use OSPF network type broadcast,  (broadcast can be used for Phase2 and phase3) 

also always Hub to act as DR - spoke is configured so that it will never be elected as the DR or BDR via the “ip ospf priority 0” 

[shammasnawaz]

There is nothing changed in configurations.

[MHM Cisco World]

So to make me understand this not new config it real life worked network. 
you mention 
""10.10.50.1 THIS IP is loop back IP of my core 1 and 10.10.50.2 this one is loop back ip of my core2 please help me why i received logs on my router, When received this logs due to this packets drops from internet and also packet drops from LAN to Router.""
what you meaning of this ??