PostgreSQL function , query disappear after long time

We are facing an issue in production environment using PostgreSQL v14, we have a function which is selecting datas from a table then aggregate these data and then insert these aggregated data in another table. At the end of the function we are updating a table with the time of execution of this function (thus we know that the function went to the end of the process). We are executing this function or from dbeaver or from a java client The problem : When having a large set of data to aggregate, it can take more than 1 hours, we noticed that if that take more than 1 hours, the query seems to disappear from the pg_stat_activity and we dont get any return on the client side (dbeaver or java) and nothing is commited . If the set of data is small (taking less than one hour), then we see the query becoming "idle" and we can see that our table has been updated. We speaked with the database administrator and he said that there is no timeout configured on the database and that we should check the network (all these activites are done under a private network of our client using a VPN). If anyone already had a similar issue and can help it would be very helpful :). Thanks.