Rebalance fail with {service_rebalance_failed,cbas,{lost_connection,shutdown}}

[ns_server:debug,2018-04-03T14:01:55.901-07:00,ns_1@172.23.104.16:leader_activities<0.6305.0>:leader_activities:handle_activity_down:548]Activity terminated with reason {raised,

{exit,

{service_rebalance_failed,cbas,

{lost_connection,shutdown}},

[{ns_rebalancer,

'-rebalance_topology_aware_service/4-fun-1-',

5,

[{file,"src/ns_rebalancer.erl"},

{line,633}]},

{misc,with_trap_exit,1,

[{file,"src/misc.erl"},{line,2283}]},

{ns_rebalancer,

'-rebalance_topology_aware_services/4-fun-0-',

4,

[{file,"src/ns_rebalancer.erl"},

{line,600}]},

{lists,filtermap,2,

[{file,"lists.erl"},{line,1302}]},

{ns_rebalancer,rebalance_services,2,

[{file,"src/ns_rebalancer.erl"},

{line,534}]},

{ns_rebalancer,rebalance_body,6,

[{file,"src/ns_rebalancer.erl"},

{line,724}]},

{async,'-async_init/4-fun-0-',3,

[{file,"src/async.erl"},{line,201}]}]}}. Activity:

{activity,<0.15297.143>,#Ref<0.0.98.26305>,default,

<<"1e5cb47103944cce7fb5ed5747714abd">>,

[rebalance],

majority,[]}

[error_logger:error,2018-04-03T14:01:55.902-07:00,ns_1@172.23.104.16:error_logger<0.6.0>:ale_error_logger_handler:do_log:203]