A Custom Member created in Query Workspace is not available to be selected in Report/Analyze/Limit/Filter By on a measure or report page in Preview mode.
SAP SuccessFactors Workforce Analytics
Custom members are not automatically available to all users once created. They must be shared in the Status section of the Custom Member menu.
Click any red X's to turn them into check marks to share a custom member.
The other possible reason you might not see what you're looking for is that a custom member based on a structural dimension (e.g. Org Unit) will appear in Report By and Limit By but not Analyze By or Filter By. The reverse is true of custom members based on analysis options. Look in the same place you would expect to find the dimension on which the custom member is based.
KBA , LOD-SF-WFA , Workforce Analytics & Planning , Problem