Not able to ping the default subnet

I can't ping the default gtw 10.15.224.1 or anything else except 10.15.224.8. Please let me know what am I missing. Thanks!

HP-2530-48G with config:
no stack
ip default-gateway 10.15.224.1
interface 48
   name "UPLINK-to-CiscoSW"
   exit
snmp-server community "public" unrestricted
vlan 1
   name "DEFAULT_VLAN"
   no untagged 1-47
   untagged 48-52
   ip address dhcp-bootp
   exit
vlan 710
   untagged 1-15
   tagged 48
   ip address 10.15.224.8 255.255.255.128
   exit
......
no tftp server
no dhcp config-file-update
password manager

--HP Switch port 48 uplink to Cisco 2960 sw config:
interface GigabitEthernet1/0/49
 switchport trunk native vlan 710
 switchport trunk allowed vlan 710-750
 switchport mode trunk