Hello Shalendra,
By default the ASA uses UDP 514 port for sending the sysylog information . So port no 516 cannot be configured. The port range has to be in the range of 1025-65535
ciscoasa(config)# logging host tftp 1.1.1.1 udp/516
WARNING: interface Ethernet0/1 security level is 0.
ERROR: Port '516' is not within the range 1025-65535.
Regards,
Bhavik Shah