domain name system - cname record to rhcloud.Com not working anymore

I have a website hosted at rhcloud.com. I added 2 years ago a cname on my domain name dp-global.vn to redirect to the website (gdp-robertduy.rhcloud.com).
Today it is not working anymore and the website via my domain name is not reachable.
I just checked the dns lookup of my domain name : it resolves to 54.196.200.207
this ip address belongs to amazon (amazonaws) therefore I think rhcloud.com is using amazon cloud.
Would you know what could prevent the cname record to work now ?

Here is the DNS records :

dp-global.vn.   0   NS  dns107.ovh.net.         

dp-global.vn.   0   NS  ns107.ovh.net.      
dp-global.vn.   0   MX  1 mx0.ovh.net.  
dp-global.vn.   0   MX  100 mxb.ovh.net.    
webmail.dp-global.vn.   0   A   213.186.33.83   
www.dp-global.vn.   0   A   213.186.33.5    
dp-global.vn.   0   CNAME   gdp-robertduy.rhcloud.com.  
ftp.dp-global.vn.   0   CNAME   ftp.cluster013.ovh.net.     
imap.dp-global.vn.  0   CNAME   ns0.ovh.net.    
mail.dp-global.vn.  0   CNAME   ns0.ovh.net.    
ox.dp-global.vn.    0   CNAME   ox.ovh.net.     

pop3.dp-global.vn.  0   CNAME   ns0.ovh.net.    
smtp.dp-global.vn.  0   CNAME   ns0.ovh.net.    
wm.dp-global.vn.    0   CNAME   ns0.ovh.net.    
www.dp-global.vn.   500 TXT "1|dp-global.vn"    
dp-global.vn.   600 SPF "v=spf1 include:mx.ovh.com ~all"

(www.dp-global.vn redirects to dp-global.vn with OVH redirection)

Thank you