Hello,
I'm using the esri QT Runtime 10.2.6 on Red Hat 7.1 x64, with the latest version of qt libraries(5.5). I was trying the example on esri site Dynamic map layer (https://developers.arcgis.com/qt/cpp/sample-code/dynamic_map_layer_sample.htm) and map control does not display anything, those are the results.

This is the log file
Starting server
Local server process started
'apppid' = '8433'
'cleanuponshutdown' = ''
'crashdump' = 'full'
'datadir' = '/tmp'
'enablehtmlviews' = ''
'logging' = ''
'onlinux' = ''
datadir does not exist, creating: "Z:\tmp\arcgisruntime_8"
Message : DataDir : Z:\tmp\arcgisruntime_8
Enabling logging
Message : Log file path : /tmp/ArcGISRuntimeLogs/arcgisruntime_8.log
Message : AppDataLocalDir : C:\users\valerio\LO~SSGOF\ArcGISRuntime
Message : AppDataRoamingDir : C:\users\valerio\LO~SSGOF\ArcGISRuntime\Roaming
Message : AppDataCommonDir : C:\users\valerio\LO~SSGOF\ArcGISRuntime\Common
Message : MyDocumentsDir : C:\users\valerio\LO~SSGOF\ArcGISRuntime\Documents
Message : CrashDumpPath : Z:\tmp\ArcGISRuntimeErrorReports
Message : Licensing level : demo:standard:0
2016-03-11 11:57:32,322: INFO rid= 'server' WebServer - Starting server on port 50000
2016-03-11 11:57:32,322: INFO rid= 'server' PionScheduler - Starting thread scheduler
2016-03-11 11:57:32,323: INFO rid= 'server' WebServer - Added request handler for HTTP resource: /ySbCq9/outputdir
2016-03-11 11:57:32,323: INFO rid= 'server' WebServer - Loaded static web service for resource (/ySbCq9/outputdir)
2016-03-11 11:57:32,323: INFO rid= 'server' AdminWebService - Creating.
2016-03-11 11:57:32,324: INFO rid= 'server' WebServer - Added request handler for HTTP resource: /ySbCq9/arcgis/rest
2016-03-11 11:57:32,324: INFO rid= 'server' WebServer - Loaded static web service for resource (/ySbCq9/arcgis/rest)
2016-03-11 11:57:32,324: INFO rid= 'server' WebServer - Added request handler for HTTP resource: /static
2016-03-11 11:57:32,325: INFO rid= 'server' WebServer - Loaded static web service for resource (/static)
Message : Server version : 10.2.6.4161
Message : Server listening on : http://127.0.0.1:50000/ySbCq9/arcgis/rest
2016-03-11 11:57:34,426: INFO rid=1 'server' AdminWebService - POST admin/createService?filePath=/home/valerio/arcgis/runtime_sdk/qt10.2.6/sdk/samples/data/mpks/USCitiesStates.mpk&maxRecords=1000&name=USCitiesStates.mpk&type=MapServer&f=json
2016-03-11 11:57:34,428: INFO rid=1 'server' mpk - Creating.
2016-03-11 11:57:34,428: INFO rid=1 'server' mpk - Create
2016-03-11 11:57:34,428: INFO rid=1 'server' mpk_host - Creating.
2016-03-11 11:57:34,432: INFO rid=1 'server' mpk_host - Launching.
2016-03-11 11:57:34,510: INFO rid=1 'server' mpk_host - Launched process 47
And thi is the local server REST page
what is the problem for you?
Thanks