asked on February 6, 2026
2026-02-06 11:53:15.0660 | ERROR | The given key was not present in the dictionary.
at System.Collections.Concurrent.ConcurrentDictionary2.get_Item(TKey key)2 allMembers)
at Flexmonster.Accelerator.Models.DataSetVO.GetColumnsList(Axis axis, String[] columns, String[] measures, ConcurrentDictionary
in C:\Git\PIVOT\projects\Datasource Proxies\Microsoft SSAS\Flexmonster.Accelerator\Flexmonster.Accelerator.Core\Models\ValueObjects.cs:line 269
at Flexmonster.Accelerator.Models.DataSetVO.FromItem(CellSet input, String[] rows, String[] columns, String[] measures, ConcurrentDictionary`2 allMembers,
Boolean formatted) in C:\Git\PIVOT\projects\Datasource Proxies\Microsoft SSAS\Flexmonster.Accelerator\Flexmonster.Accelerator.Core\Models\ValueObjects.cs:line 219
at Flexmonster.Accelerator.Controllers.FlexmonsterProxyController.<Execute>d__34.MoveNext()
in C:\Git\PIVOT\projects\Datasource Proxies\Microsoft SSAS\Flexmonster.Accelerator\Flexmonster.Accelerator.Core\Controllers\FlexmonsterProxyController.cs:line 826
⋅ February 9, 2026
Hello George,
Thank you for contacting us.
This error usually indicates that Flexmonster Accelerator was restarted while in use, and the previous state was cleared. This behavior can also occur when Flexmonster Accelerator is scaled across multiple instances.
To better understand the cause, please provide us with more details on your use case:
It will greatly help us.
Additionally, we will handle this exception and replace it with a more descriptive error message with ETA March 2nd. At the same time, we will still need the details mentioned above to identify the root cause of this error in your use case.
Looking forward to hearing from you.
Kind regards,
Nadia
⋅ March 3, 2026
Hello George,
We are glad to let you know that the exception when accessing members during query execution was handled in Flexmonster Accelerator.
It is included in the 2.9.124 version of Flexmonster: https://www.flexmonster.com/release-notes/version-2-9-124/.
You are welcome to update the component. Here is our guide on upgrading to the latest version: https://www.flexmonster.com/doc/updating-to-the-latest-version/
Additionally, Flexmonster Accelerator needs to be updated: https://www.flexmonster.com/doc/updating-to-the-latest-version/#accelerator.
You are welcome to contact us if other questions arise.
Kind regards,
Nadia
