Update - it appeared to be miss-configuration NAS (Synology) -> Switch (TP-Link). You can combine interfaces together, using LACP - that what I did. On switch, I configured LACP and on Synology NAS you can choose one of the LACP modes. I tried Adaptive Load Balancing, IEEE 802.3ad and Active/Standby. Trying tonight, the Balance XOR mode fixed the issue 🤔 It looks like the LACP on TP-Link is Static Link Aggregation (not that you have a choice there).    I am very disappointed with TP-Link - fair enough is half price of Meraki Go PoE switch but the way you configure it - it's just pain. You get what you pay for, looks like.    The strange thing is all devices wired (eth cable) were working fine - just all devices connected to the network by WLAN (MerakiGO GR12) had an issue with accessing the NAS.   Thanks @Xydocq  ... View more

Thanks, @Xydocq, for the reply.   It's not that. I am getting 192.168.20.10 from WLAN and 192.168.20.11 from LAN for the laptop. It is strange behave. I can ping router VLAN interface from WLAN but the NAS IP 192.168.20.252   As all on the same VLAN there is no router involved, but there are any:any rules on that VLAN anyway. No packets from laptop on WLAN can be seen on NAS interface. The packets must be dropped on AP for some reason. Any way to confirm that?  ... View more