When Call Export Web Map Task—ArcGIS REST API: Services Directory | ArcGIS for Developers with Client Side graphics (ExportWebMap specification—ArcGIS REST API: Services Directory | ArcGIS for Developers ),
Return Format: JSON
Request Method: Post
the service sometimes return Gateway timeout error, and return an empty image(as 2kb size) most of the time. I checked the info/log on the server,but there is not any exception or error output.
Also, the I've tested on these services:
it returns images normally, but sometimes empty images unpredictably either.
Does any one encounter with this?