Hi Fiaz Ur Rehman,
Thank you for posting in the Microsoft Community Forums.
Ensure that the network connection between the server and the client is open.
Test the network connection and port reachability using tools such as ping or telnet.
Ensure that the DNS settings on the client are correct to resolve to the IP address of the domain controller.
Check for correct SRV records in the DNS server.
Log on to the server and check the relevant log files (e.g., system logs, security logs, etc.) for more detailed information about the denial of access.
Ensure that the client is using the correct protocol and port to try to connect to the server.
Check if the client is sending too large packets.
Best regards
Neuvi Jiang