@David-TP Hi, the subnet mask is 255.255.255.0, the two issues: I can connect to the NAS with my mobile phone only if I am connected to the x20 deco, when the mobile phone connects to one of the x50...

I installed a deco x20-4G modem with updated firmware 1.1.4 build 20230714 rel. 2881. This modem is connected to a poe switch where are connected a nas and two deco x50 poe units with firmware 1.2.4...