Kibana Machine Learnign Internal Server Error

With the basic licence i want to learn how the Kibana ML works, i've an index with more than 2milion of documents and when i select "Search all" instead of "Sample size(per shard) 100000" i receive

Error loading data in index my_index. Internal Server Error

What could be?

Elastic ML only works with a Platinum license or a Trial license.

With the basic you have the ML Data visualizer, but i think the problem is the power of the machine where Elastic is running.