Nighthawk Switch Not allowing android apps access to Synology NAS

[Snow_RE]

I have been having problems connecting to my Synology Nas with the DS file and DS Finder apps on my phone. These apps worked perfectly with my first Nighthawk switch, but I had to RMA it for this one as it was dropping connection to the internet.
The apps both find the Nas's IP address so they can see it on the network but will not allow me to connect to the Nas.
when I enter the username and password and hit connect, I get a time out error asking me to check connection to the server and the usual is the IP correct so on so-forth.
These apps work perfectly if I change the switch to my tp link switch which is an unmanaged switch, so this indicates to me that the issue is with the Nighthawk switch.
I’ve looked at the settings of my Nighthawk but I don't see anything obvious to me as to what maybe causing the issue.
I have updated the firmware to the latest 1.7.1.1 and everything else is set as default except for link aggregation which I have set up on port 3 and 4 to my NAS. I have tried it without the link aggregation on the Nas but still no connection.
any ideas would be greatly appreciated

[schumaku]

That's more than strange, considering the discovery (e.g. using IP broadcast, some IP multicast like Bonjour) is much more tricky than the pure L2/L3 traffic.

Do the Apps allow connecting to a LAN IP without using the discovery?

Are you convinced that the NAS LAG is properly configured (and how)? Easy possible considering the LAG config is still more than confusing with the Static/LACP control implemented as an ugly switch on the UI (Off is static, On is LACP in my understanding).

This reads to me more like a LAG config on the switch and the NAS side, or less likely (as the non-managed switch just works) some MTU issues with the NAS configured to Jumbo Frames while the mobile wireless is typically on a more standard frame size, and the NAS might block some of the PMTUD return traffic based on ICMP. 

[Snow_RE]

Thanks for the reply Schumaku,
I have finally got it to work, not sure what the issue was still? I factory reset the switch in the software originally, updated the firmware and reset my lag unable to connect to the NAS.
Then the other day I decided to reset the switch with the reset button and set my lag up again, low and behold everything is working fine now. As far as I know its the same thing? Just glad to get it up and running again. It's been a lot of trouble for me this Switch, the first one I had I had to RMA with the help from Netgear tech support kept dropping connection to the net and then running slow. After a couple of months of back and forth communications (Iwork away from home a lot and takes a while before I get chance to reply to emails)a wireshark report later and they sent me a replacement but by this time my tech support had expired so had to post here.
Once again many Thanks for your help!