ERROR | The given key was not present in the dictionary.

Answered
George Antoniou asked 6 days ago

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)
   at Flexmonster.Accelerator.Models.DataSetVO.GetColumnsList(Axis axis, String[] columns, String[] measures, ConcurrentDictionary
2 allMembers) 
   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

1 answer

Public
Nadia Khodakivska Nadia Khodakivska Flexmonster 4 days ago

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:

  1. How often is the Accelerator refreshed or restarted?
  2. Is the Accelerator running as a single instance or multiple instances?

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

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