Dns servers appearing twice on curriculum server

[password1234]

Hi all

 

Recently did some server migration for school

 

Set as below

 

Admin.domain (an admin server for admin users

 

Old server was 2008 so we installed a new server dc promod it to 2016, both servers are still online and we plan to demote the old one soon both running as dcs currently and admin machines are fine

 

Curriculum.domain (curr server for students and teacher) running 2012

 

Both servers can speak to each other we have established trust

 

Now all of a sudden after migrating the admin server to 2008 a 2016 by dcpromo on the curriculum server under dns we now see 2 dns server

 

One called

Curr-server

 

The other

Curr-server.domain name

 

Both with identical records

 

Now the biggest problem we have is that none of the student machines that sits on the curriculum network can logon says cannot logon to domain

 

Any ideas why duplicate dns entries will all of. Sudden appear on the curriculim side? Surely work done on the admin migration should not have affected thing

 

All on the same IP range

 

Anyone have any ideas?