Try to add these lines to your tigercoin.conf file:
addnode=37.187.99.137
addnode=5.9.94.205
addnode=88.172.65.144
addnode=193.27.209.102
addnode=66.55.133.86
addnode=173.160.57.11
addnode=95.34.194.195
addnode=95.85.40.89
If that doesn't work, check whether your system clock is in sync with the rest of the world.