Client UDP packet to wrong server interface

we have several VLANs in our network. One of our VLANs has only a few clients on 192.168.50.x and they did the backup using the internet mode to our backup server on

But now I added a new link for the backup server in this VLAN : and removed the internet mode for the client group.

But I still see in our firewall packet coming from the client to the server:
21:58: DENY_LOCAL - UDP-Paket von nach - Paket zurückgewiesen

How can I configure the client so that he contacts the server on ??