Apple iMac hangs when connected to Plusnet router

[#1]

My iMac works fine until I connect it to the Plusnet router and then it hangs. The only fix is to disconnect from the router. This wasn’t a problem with my previous bt router so don’t know why it’s an issue now. 

I’ve attempted the fix seen in a previous post (see all below) but can’t do it as after I log into the Hub using 192.168.1.254 and go to ‘Advanced Settings’ there isn’t a ‘Wireless’ tab for me to go into in order to change the SSID name and untick the synch with 5Ghz on the 2.4 section.

PLEASE HELP!!!!!

PREVIOUS FIX INFO:-

https://www.youtube.com/watch?v=b8CDfkR4wZU

https://community.plus.net/t5/My-Router/Changing-SSID-name-2-4GHZ-and-5GHZ/td-p/1507109

You have to uncheck the  synch with 5GHz on the 2.4GHz section ,

see post 4 here

https://community.plus.net/t5/My-Router/Making-5-GHz-have-separate-SSID-with-the-Hub-One/td-p/134955...

[#2]

Those instructions are for the Hub one router , which router do you have ?

If it helps you can identify it from the pictures here https://www.plus.net/help/broadband/router-setup-guides/

[#3]

If you've still got your BT router then use that instead of the Plusnet offering. You will find the instructions required to get it to work with your Plusnet account on this board.

[#4]

Cheers.
I believe I have the 2704n router.
Any help would be appreciated.

[#5]

I believe I have the 2704n router.

@Jimmymc50 that would explain why you can't find the way to separate the wifi networks , it only has the 2.4ghz!

TBH it's not a very good router.

Take @Baldrick1 's suggestion , use your old BT Hub

Instructions here  for Hub 5 https://community.plus.net/t5/Fibre-Broadband/using-BT-Home-Hub-5-on-PN/m-p/1192173 there's alos links in there for Hub 2,3,4

[#6]

Cheers mate.
Out of interest I don’t suppose you’d know why it’s causing the issue?
My bt WiFi was awful and kept throwing me out whereas this one is working really quickly on my phone.

[#7]

Try turning off IPv6 on your iMac.

[#8]

I've also read in the past that turning off a Mac bluetooth feature can fix wireless problems even when the bluetooth was not actually used.

The other point to consider is that if your BT router is a dual band type, I believe that most are, you should try separating the bands in the same way as for a Hub One. The Hub One is a HH5A with tweeked firmware.