SBC Not routing outgoing calls

[walruses]

Hi everyone I´m facing a new challenge with SBC hope you can give me your opinion.

I´m trying to make outgoing calls so I can separate traffic from two different clients.

Client "A" uses SM "A" and outgoing traffic is working fine via interface B2
Client "B" uses SM "B" and I´m trying to use same interface B2 for outgoing calls but calls never touch interface "B2", SBC rejects all calls with a "Server Internal Error"

B2 has a public ip address and receive correctly traffic from different clients.
Both SM´s use the same SBC.

Any idea?

Best regards.