Cannot connect to BT wi fi using a Mac, iPhone or iPad, but can on a Windows 10 box.

[toobi-won]

I lost the ability to connect to my BT wi fi using any Apple hardware last night after signing out from BT Fon, I have tried signing back in with out success. BT TV works fine and am currently using an old Sky router duplexed to my home hub via a lan cable to provide me with a (slower) wi fi connection. I have reset my HH to factory settings but still unable to connect using anything from Apple. Any suggestions most gratefully received.

[pippincp]

Split your wireless networks and turn off smart setup.

https://www.bt.com/help/broadband/fix-a-problem/broadband-and-wi-fi/i-want-to-improve-my-wi-fi/how-d... 

[toobi-won]

many thanks, I will check this out.

Update to original message, I was able to connect to my BT wi fi, this morning, on all devices. I went to the broadband manage page to see if I could re enable BT Fon (previous attempts did not have the sign in check box but the disable had the message "sorry to see you go, click below to continue", which suggested I hadn't  disabled it at this point. Clicking continue lost my connection to my BT wi fi ,so had to use my old Sky box connected to my hub via ethernet.
Going back to the BB manage page, I found I could sign up for BT Fon but when I tried to do so, an error message popped saying that there was an error with this account, which was trying to be resolved.
I am currently connected to my BT wi fi, will see how long it lasts.
Again, many thanks for you reply.

[toobi-won]

Lost connection to BT wifi ten minutes after posting the above. Nothing worse than an intermittent fault.

[toobi-won]

Tried the solution in pippincp's reply, split the network, renamed the 5G without spaces, selected wifi, asked for password, inputted, thought about it and asked for it again. Still cannot connect to BT wifi.