specific I don't know what's going on, there is a similar mistake explanation I remember the code below is in this way, you are looking for data validation is on the left side of digital should be behind the Numbers of the corresponding explain is wrong
1. The Router - same ID

Ospf neighbor set up two devices, when the equipment the Router ID - consistent, will think the other send a message to himself, not accept ospf neighbor,

2. The area ID inconsistent

If two devices connected to the interface in different area, will cause the failure of ospf neighbor build,

3. The inconsistent authentication

If in two different device interface configured on ospf authentication, because the authentication failure, will lead to ospf neighbor build up,

4. The mask is inconsistent (MA) in a network

MA in the network needs to choose the DR and BDR, when the mask is not consistent, cannot choose the DR and BDR, leading to ospf neighbor build failure,

5. The hello and dead inconsistent

Two devices configuration hello/dead time, will cause the failure of ospf neighbor build,

6. Silent - interface (silent port, port don't accept not hair)

On port configured on the port command, silent port for the message, don't accept not hair, no message communication, nature also cannot ospf neighbor relationship,

7. The priority in the MA network ()

In MA in the network, need to select the DR and BDR, when equipment have priority to 0, all equipment that do not participate in the DR and BDR, election, also leads to ospf Lin establish failure

8. net work inconsistent

In configure ospf, we will declare port address, can make the ospf, when two devices connected to the link on the declared the completely different network segment address, also caused the ospf neighbor build up,

9. MTU value is inconsistent