Problem with lumberjack and beats

I'm receiving every X hours this error.

{:timestamp=>"2016-05-06T13:42:07.484000+0200", :message=>"CircuitBreaker::rescuing exceptions", :name=>"Lumberjack input", :exception=>LogStash::SizedQueueTimeout::TimeoutError, :level=>:w
{:timestamp=>"2016-05-06T13:42:07.585000+0200", :message=>"Lumberjack input: The circuit breaker has detected a slowdown or stall in the pipeline, the input is closing the current connectio
n and rejecting new connection until the pipeline recover.", :exception=>LogStash::CircuitBreaker::HalfOpenBreaker, :level=>:warn}

And for beats, this:

{:timestamp=>"2016-05-11T01:19:07.750000+0200", :message=>"Beats input: the pipeline is blocked, temporary refusing new connection.", :level=>:warn}
{:timestamp=>"2016-05-11T01:19:07.751000+0200", :message=>"CircuitBreaker::Open", :name=>"Beats input", :level=>:warn}

I don't know why is this happening. It can be for 2 or 3 minuts giving this errors.
Can someone tell me why is this happening, or how to debug in roder to know what is causing this?

Thank you all