Kibana: unexpected character at line 1 column 1 of the JSON data

Hi,

I'm just implemented elastic stack as a log analyzer and still learning to use it.

I have a problem with kibana on a dashboard with multiple visualizations. When I'm trying to show all visualizations from 2 months ago to present an error occured like this "[esaggs] > JSON.parse: unexpected character at line 1 column 1 of the JSON data" over and over again with multiplied "[esaggs]". But when I'm trying to show all visualizations from a month ago to present is successful.
Futhermore on the other dashboard with multiple visualizations is successful to show all visualizations even from 3 months ago to present.

My questions are:

  1. What is the meaning of this error message?
  2. Which one is the problem? kibana or elasticsearch?
  3. Where I can find more detailed error message to solve this problem?

Additional information:

  • elasticsearch and kibana are ver. 7.6.2
  • elasticsearch single node mode
  • openjdk ver. 13.0.2
  • 4 CPU and 8GB memory

Regards,
Ade