When I checked, even I was unable to connect to SQL Server remotely using SSMS and using credentials of domain A.
However when I tried to RDP the server using domain A's credential it was working fine and there after remote access to SQL server also started working fine.
I researched this issue on web and found two solutions to fix it.
One was to fix malfunctioning DC and second was to restart the server where SQL Server was running.
[CLIENT: xxxxxx] We have two domains let's say A and B. In a normal scenario, both domain users are able to connect.
But few days ago, all the users from domain A were unable to connect to SQL Server running in domain B.
However domain B users were able to connect it successfully.
So it looked to me like when I RDPed the server something got refreshed and my login remotely started working fine.I was sure that the actual issue was something related to AD and kerberos authentication but unable to prove so.