Maps in dashboard PDF or PNG reports are not showing EMS tiles

[LeeDr]

Kibana version: 7.4.0 (7.x snapshot)

Elasticsearch version: 7.4.0 (7.x snapshot)

Server OS version: Ubuntu 16.04

Browser version: Chrome

Browser OS version: Ubuntu 16.04

Original install method (e.g. download page, yum, from source, etc.): tar.gz default distribution

Describe the bug: 7.4 is an improvement over 7.3 in that the data regions from a Map on a dashboard do print, but the country outlines, or borders, boundaries, don't print.

Steps to reproduce:

1. Load the eCommerce sample data

2. Go to the [eCommerce] Revenue Dashboard

3. note the rendering of the map;
   

4. Share > PDF Reports > Generate PDF

5. open the completed PDF report and check that maps isn't completely rendered;
   

6. try again but select Optimize for printing

7. check the report, still not completely rendered (several other visualizations also didn't render completely);
   

8. remove all other visualizations from the dashboard except the map. Generate a new PDF report

9. I thought there was a chance that this map only dashboard might render completely if it was just a timing issue, but the map still looked the same, data layer but no borders;
   

Expected behavior: Map should render completely (similar to how it looks on screen)

Screenshots (if relevant):

PDF default rendering:
[eCommerce] Revenue Dashboard.pdf

PDF Optimized for printing:
[eCommerce] Revenue Dashboard (optimized).pdf

PNG:

Errors in browser console (if relevant):

Provide logs and/or server output (if relevant):

Any additional context:

[elasticmachine]

Pinging @elastic/kibana-gis

[nreese]

Looks like the tiles are not EMS tiles are not loading. @nickpeihl Any ideas? CORS issue?

[nreese]

Changed title to "Maps in dashboard PDF or PNG reports are not showing EMS tiles"

[nyurik]

I have warmed up zoom 0-6 on all the caching servers, so they should serve things quicker now. https://github.com/elastic/infra/pull/14153 not sure if this is related.

[nickpeihl]

Maybe CORS issues, or maybe the tiles simply haven't loaded yet. Would be interesting to see if extending the _startInitialLoadRenderTimer timeout changes the outcome.

[thomasneirynck]

Thanks 💯 @joelgriffith ! Closed with #55137