Having problems setting up a Samba file share

Hi, I am having issues setting up a samba file share. The server is redhat 7.4. I am also testing on a 7.2 server and having the same problems.

I am trying to set up file shares that can be accessed from Windows PC's.

I connected the server to our work domain using realmd. So it can be logged into using domain credentials.

I have tried setting up the shares to be accessible but just keep being prompted for a username and password when trying to browse to the mapped drive. I have tried it both using the a domain group and even just a local user on the server. Have done the same on the 7.2 server.

No matter what I try I just keep getting prompted for a username and password and no passwords work.

Is this a common thing to happen? Been through too many "how to" guides now and nothing works.