If your Kibana dashboard has the following charts Area, Line, Bar (horizontal/vertical) and Heat Map and if the x-axis buckets of the chart have Date histogram aggregation ie Timestamp set then the x-axis values are not visible in the PDF report generated by Skedler.
Area chart in Kibana dashboard
Skedler PDF report of the Kibana dashboard
This is due to a bug in Kibana. Hence when Skedler loads the Kibana URL to generate the report, the x-axis is not appearing.
Please refer to the Kibana forum discussion link for the issue mentioned,
As per the forum discussion, Kibana will fix the issue in the upcoming release. Once the issue is fixed with Kibana, Skedler will generate the report without any problem.