Access denied when trying to delete files with xp_cmdshell
You need to have a connection as well as permissions. SQL Server won't automatically connect to a network resource. You can do this either inside or outside of SQL Server but the connection has to be made on the machine. If there is a permission issue, then the 'net use' in the SQL query will return more info than just 'Access Denied'.

exec xp_cmdshell 'net use \\morrison\backups\angelia\AS_ReportingServicesDW_MOLAP mypassword /USER:ntdomain\angeliasql'

exec xp_cmdshell 'del \\morrison\backups\angelia\AS_ReportingServicesDW_MOLAP\ReportingServicesDW_MOLAP-20151116.abf'