WiFi on iPhones are extremely slow

[#1]

So we've got 5 Apple devices, one Note8 Samsung connected via wireless and two TVs connected via ethernet cable to the Hub one.

Connection on the TVs and Samsung phone are perfect no issues. However, on the Apple devices it's extremely slow. I've tried internet speed tests and I'm getting 1mb down and 0.2 up. I've tried to do this https://community.plus.net/t5/My-Router/Devices-stop-working-on-5-GHz-connection-Wifi-drops/m-p/1395...

But it hasn't worked. Is there any other way I can try to fix? Is it the router that's faulty?

Thanks

[#2]

Have you tried rebooting the router?  I have to do this every few weeks to keep the WiFi speed up.  Another thing to try is to go into the wireless settings in the router and if "Channel selection" is shown as "Automatic (Smart wireless)" click the 'Refresh' button at the bottom of the page (I suspect rebooting the router will have the same effect - next time mine gets slow I will try refreshing the Smart Wireless instead of rebooting).

If the channel selection is manual then you may have chosen a channel which is conflicting with other routers nearby.

[#3]

Hi @Noahmir, you might find splitting the 2.4Ghz and 5Ghz channel on the router to be of benefit to the Apple devices. I have sent you an email guide but there's also a forum post here if you prefer. https://community.plus.net/t5/My-Router/Devices-stop-working-on-5-GHz-connection-Wifi-drops/m-p/1395...

[#4]

Hello thank you for your reply.
I tried the first option and it worked for about 30 minutes perfectly and then it stopped, whenever I try to connect to it again, an "authentication error" comes up.

[#5]

Hello cheers for the reply,
Unfortunately I tried this and it hasn't worked.
But thank you anyways.