SBC failed to add flow-by-port / MBC Event [144='1']

Hello Community,

a customer is experiencing call drops. From the logs i can see that the SBC disconnects both legs with a BYE message.

When i look at the RTP streams on the one side where i can see them there are packets worth 10 seconds of payload missing in the direction to the gateway.

customer <-> SBC <-> gateway  

Atm i cannot see the customer side streams cause our Palladion System doesn't like us anymore. The customer side uses SRTP while the gateway side is not encrypted.

In the logs i see that the SBC is disconnecting the both call legs 10 seconds after i get this log entry in mbcd log: