I ping, your server change name to solo4.ckpool.org, 395 ms.
Too slow?

jack1@hp:~$ ping solo.ckpool.org -c 5
PING solo.ckpool.org (51.81.56.15) 56(84) bytes of data.
64 bytes from solo4.ckpool.org (51.81.56.15): icmp_seq=1 ttl=38 time=512 ms
64 bytes from solo4.ckpool.org (51.81.56.15): icmp_seq=2 ttl=38 time=433 ms
64 bytes from solo4.ckpool.org (51.81.56.15): icmp_seq=3 ttl=38 time=355 ms
64 bytes from solo4.ckpool.org (51.81.56.15): icmp_seq=4 ttl=38 time=379 ms
64 bytes from solo4.ckpool.org (51.81.56.15): icmp_seq=5 ttl=38 time=300 ms

--- solo.ckpool.org ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4000ms
rtt min/avg/max/mdev = 299.737/395.647/511.561/72.009 ms