Hello Nabil
I assume you mean the connectivity between the two disjointed “area 0” regions…
Note that when you enable authentication, even if you do so on only one router, OSPF will continue to function until the OSPF process is reset. If it is not, then nothing will change yet. After resetting the OSPF process, the virtual link should fail, and you will see that the two area 0s will not create a neighbor adjacency.
I hope this has been helpful!
Laz