Unable to save: error(Sequence contains no matching element)

Hi,
Can you add the full callstack (click "copy to clipboard" and add to text file as attachment).
Does the problem occur with every save? Or when you do a specific thing in Designer Studio?
Please let me know what version you are working on.

Best regards,
Przemek

This is the callstack from the error. This is happening when I am trying to connect a data source to a field
Version:2021.1.3.163



Type: WebCon.WorkFlow.Studio.Logic.Exceptions.WebserviceSaveException
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Message: Sequence contains no matching element
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CallStack
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at WebCon.WorkFlow.Studio.Logic.PortalService.PortalService.SaveProcess(MappingsToSave model)

at WebCon.WorkFlow.Studio.Logic.Managers.ProcessesManager.SaveWithoutCheckingByWebService(Process process)

at WebCon.WorkFlow.Studio.Logic.Managers.ProcessesManager.SaveWithoutChecking(Process process, MapperObject mapperObject, Boolean useSaveChangesContext)

at WebCon.WorkFlow.Studio.Logic.Managers.ProcessesManager.Save(Process process, Boolean checkIsProcessModifiedByImportExport)

at WebCon.WorkFlow.Studio.Forms.ModuleProcess.ProcessController.LockPanelAndExecuteSave[T](T entity, Func`2 validateAction, Func`2 saveAction)
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