Unable to login to SQL Server using SSMS and SQL agent failing
Fix for my this question was to apply   


.NET framework 4.6.1   
ADO.NET - SqlClient (.NET Framework 3.5/.NET
Framework 2.0 SP2) from this link
https://support.microsoft.com/en-us/kb/3135244.


These fixed the local login and SQL agent service issues. Then the new issue surfaced i.e. unable to SSMS this server from other servers. 

To fix this I had to enable ‘KEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Hashes\SHA’ in registry. After enabling it remote connection started working fine.