set up two dns with public IP master and slave

[crisstm]

Hi all,

i want to set up two server from diffrent location one master and one slave .
i need to obtain redundancy and when the first server goes down must to work the second and when the secondary server goes down work to primary, and when work both obtain redundancy.
here i explain what i do:
to my registrat i tell
ns1.xdigital.ro 89.122.18.58
ns2.xdigital.ro 86.34.232.110
that's my public ip where is located my servers

on my ispconfig to first server i set up:

*Management->Server->Settings
Hostaname ns1
Domain xdigital.ro
Ip 89.122.18.58
IP List 89.122.18.58
86.34.232.110
DNS tab on
default Ns1 89.122.18.58
default ns2 86.34.232.110

*ISP Manager->ISP Site->Hostname www
Domain xdigital.ro
IP 89.122.18.58

*DNS Manager->xdigital.ro as a primary domain
Domain SOA xdigital.ro
IP 89.122.18.58
In Option tab i set up
Nameserver 1: ns1.xdigital.ro
Nameserver 2: ns2.xdigital.ro
On the Records tab i set up the A record
Hostname www
IP 89.122.18.58
Hostname mail same IP
Hostname ns1 same IP
at MX i set up
host mail.xdigital.ro 10 priority

on my ispconfig to second server i set up:

*Management->Server->Settings
Hostaname ns1
Domain xdigital.ro
Ip 86.34.232.110
IP List 89.122.18.58
86.34.232.110
DNS tab on
default Ns1 89.122.18.58
default ns2 86.34.232.110

*ISP Manager->ISP Site->Hostname www
Domain xdigital.ro
IP 86.34.232.110

*DNS Manager->xdigital.ro as a slave domain
Domain SOA xdigital.ro
IP master DNS 89.122.18.58

This is all but doesn't work my domain xdigital.ro. On the same server i have other domain wich is working fine. where am i wrong?
thank's in advance