Rendering issues - v6.2.4

We are unable to get rendering working correctly with the following errors in the logs.
Sending a test alert works fine but a when a real alert triggers we dont get the alert.

As an aside I would have thought the alert would be good to send even though the rendering failed. I can live without the chart but no without the alert… is this a bug ?

t=2019-06-19T10:48:31+0000 lvl=dbug msg=“Phantomjs output” logger=rendering out=“Loading a web page: http://grafana.staged-by-discourse.com/d-solo/fnoFTO2mz/ec2-instance-disk-space?orgId=1&panelId=2&render=1 status: success 30000\n”
t=2019-06-19T10:48:31+0000 lvl=dbug msg=“Phantomjs error” logger=rendering error=“signal: killed”
t=2019-06-19T10:48:31+0000 lvl=info msg=“Rendering timed out” logger=rendering

Could this simply be a memory issues ? We are not running under a docker container.

Thanks,
Serge

I have a same problem with grafana 6.5.2, does anyone have a solution for this. Thanks.