Ari disconnected in long calls?

We initiate a conference call using ARI
for calls upto few hours everything is working fine
but for long duration calls (seems that more than 3 hours) the ARI is disconnect - our program that initiate the call do no get events, for example the even that indicate that the call ended

Try to get a SIP trace of such a connection. A 3 hour calls sound ambitious, but you might be able to find out why they eventually fail.

I think the caller aid that ARI disconnected, not the SIP session.

In that case everything should be traced. The 3 hours are still ambitious, but one should know more about the connection.