VRT (5/5/2015)
May be on Server, there might be a limitation on records that you need to increase the Dimension records count.OLAP\Query\DefaultDrillThroughMaxRows
and also the RAM memory size also you may need to check out.
Memory\VertipaqMemoryLimit
That setting is just for drillthrough. There is not row limit for tabular dimensions provided that no single column has more than 1,999,999,997 distinct values.
https://msdn.microsoft.com/en-us/library/ms365363.aspx#bkmk_vertipaq
It most probably is a RAM-related issue as VRT said. Have a look at the memory allocation of the AS instance (https://msdn.microsoft.com/en-us/ms174514.aspx) and up it if needed.