You may check the TS Session logs in the event viewer under:
Applications\Microsoft\Windows\TerminalServices-LocalSessionManager\Operational
Also check the registry below:
HKEY_Local_Machine \ SOFTWARE \ Policies \ Microsoft \ Windows NT \ Terminal Services
KeepAliveEnable REG_DWORD 0x00000001 (1)
KeepAliveInterval REG_DWORD 0x00000001 (1)
Disable IPV6 and check firewall.