HiIf I am getting warning code 300 invalid customer id during ID sync, what could be the possible reasons?  I have checked the documentation @ https://marketing.adobe.com/resources/help/en_US/aam/index.html?f=dcs_error_codes and what does it meant by "missing values for data source"?

Hi,Is it possible to delete mbox locations in Adobe Target Standard/Premium? I can only see documentation on this in Classic: https://marketing.adobe.com/resources/help/en_US/tnt/help/t_Clearing_Deleting_an_Mbox.html