The list_servers (S-Lang or Python help) command returns a list of servers that may be available to the user. The list is derived by checking for local socket files used by chips. It is possible that old socket files may exist - e.g. if ChIPS exited improperly at some point - and those servers are not available for use. The check_server_exists (S-Lang or Python help) command indicates when a server is not available:

chips> check_server_exists("ChipsServer_7358_1")  # Python
False

chips> check_server_exists("ChipsServer_7358_1"); # S-Lang
0

The server named "ChipsServer_7358_1" is not actually available in this session.

The socket files are stored in /tmp/.chips.username. Delete these files to clean out the server list:

unix% rm /tmp/.chips.username/.*