The link you provided is to reference to creating a PDF or PNG report, however in my case, I'm trying to generate CSV report instead.
I did set xpack.reporting.queue.timeout (2m) and xpack.reporting.kibanaServer.port, xpack.reporting.kibanaServer.protocol and xpack.reporting.kibanaServer.hostname to their respective values, unfortunately that did not help...
.. while all of the Kibana instances are using same kibana.yml file, the values for some keys are set respectively, which includes kibana.index and xpack.reporting.index values.
I'm already using spaces, however in my case space still resides in it's own index set by kibana.index value, which I plan to change by migrating all spaces into fewer or single index.
I tried to set different value for xpack.reporting.index on one of Kibana instance, however even though I do see value is set to .reporting-XYZ and respective index was created, the report was still processed by different by Kibana instance, which has default value for xpack.reporting.index - (.reporting).
It's like Kibana instance isn't respecting it properly or something else..