Most tickets are settled by three answers: the exact message, whether it happens on one address or on all of them, and since when.
The most common messages
Error 407 is authentication: the username, the password or the authorized IP is wrong. A timeout is the path: the address exists, but the answer did not come back in time. Connection refused is the port: nothing is listening on that address and port.
If it is a single address, replacement swaps it for another at no cost, once every 24 hours. If it is all of them at once, the problem is in your network or your configuration, and swapping the whole list changes nothing.