The {0} '{1}' has an invalid TablixCell. The {2} of the TablixCell is invalid. The TablixCell cannot span columns under TablixMembers ...

The {0} '{1}' has an invalid TablixCell. The {2} of the TablixCell is invalid. The TablixCell cannot span columns under TablixMembers in the TablixColumnHierarchy that are not static siblings, and the spanned cells must all exist under the same dynamic TablixMember in the TablixColumnHierarchy, if one exists.