You will find that that network is no longer running.
At this stage each release is a new network. Only when the network is declared live will new releases continue using the same network.
Its because the nodes do not recognise the previous release nodes.
TL;DR
the network you are trying to connect to does not exist anymore. The devs are testing later releases at the moment.
The dev update topics are the best source to know when we can try out the code.