problems accessing domain sites

Question

I have a Windows Server 2008 R2, at the moment I have it with a single network card. The problem is that the clients' PCs do not have access to the web pages that are contained within the same domain, and the web browser gives me an exception "If you are connected through a firewall, check that Firefox has permission to access the Web.". I already checked everything and everything is fine, I have added exceptions to the browser so that it does not connect through the proxy and still they cannot enter. On the other hand, the server can enter without any problem and the PCs have a good connection, they see each other. Anyone know what can it be.

Answer 1

Not a lot to go on but something here might help.
https://learn.microsoft.com/en-us/windows-server/networking/dns/deploy/split-brain-dns-deployment

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