SSRS axis range minimum maximum

HI:)

I try in SSRS to display my chart with the sum of client by date.... 

i work from a cube where date are like this : 2016-12-01, 2017-01-01 .... in fact the number of client are calculated for every month so every month get for day 1st...   So i want  axis range to display label for only the month of June and December for two last years.... so in axis options i put in minimum that: =cdate(format("2015-06-01", "MMM yyyy"))

and for maximum that : =cdate(format("2016-12-01", "MMM yyyy")). Besides i choose interval equals to 6 and interval types = months but only january and july display while i want only june and december...

I don't understand what is wrong. Someone can help me?

Thank you very much :)

Vaness ;)