SSRS SQL 2012 kerberos and SharePoint 2010

We have a SharePoint 2010 sp2 in a three tier farm running on (3) 2008R2 Virtual Servers:
srv_WFE, srv_APP, srv_SSRS2012
The Content db is on srv_SQL2012 Server.
All servers are set to Delegate Kerberos Only.
We have one WebApp (sp2010.test.sp-int) in the test environment and Claims to Windows service is running on all 3 servers.
(running locally as an Admin)

Kerberos is working fine on the WFE log 4624 reads kerberos
 
We have set up SPN’s for:
Each Server
The Web Application's host name
The SSRS Service Application's Application Pool account.(test.sp-int\acctsp_rs)

All delegation is set to any service kerberos only

When trying to add datasource.rsds with conection string:
Data Source=WEB1_DEV.SQL.test.sp-int,1539;Initial catalog=Datamart;
and after testing connection it fails. Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'.

What could be the problem(s)