Have a look at Kibana only display logo no content -elasticsearch error shard - #11 by warkolm to help with reindexing.
Indices are where the data is stored, they are made of shards. In the 6.X release we defaulted to 5 shards per index with 1 replica set, so a total of 10 per index. We changed that in 7.X to be 1 per index with 1 replica (ie 2).
No need to do that! 
Though I would suggest using the latest 7.X release, as it reduces the burden here.
Otherwise you can set the shard count in the filebeat config file.