router implicit used nhop - dmvpn

[Wizard4777]

show ip nhrp gives me this " Tunnel101 created 00:15:30, expire 01:48:37
Type: dynamic, Flags: router implicit used nhop"

this makes spoke to spoke communication impossible.

please help

[MHM Cisco World]

I dont see how this prevents spoke to spoke ?

Can you more elaborate 

MHM