linkstar works-inkstar S2 Doesn't...

our problem:
Old linkstars modem work - 3 unit of linkstar S2 don't.

Satellite = AB1
NOC = Skylogic Italy
Infrastructure (antenna,BUC,LNB) = works fine with
Linkstar terminal (old version)

Using the same infrastructure with the Linkstar S2 (testing 3 modems !!!) produce the following results:
a. NOC see the terminal
b. Terminal respond to NOC
c. NOC reset terminal
d. Terminal doesn't link
e. NOC cannot explain what's wrong !!! says very strange...

Any idea ?? Do you need any screens ?

Many thanks,

Yoram Yaeli