Bell Fibre Modem Upgrade. iMac/MBAir/APTV4 on Tv no longer seeing each other

[TohMac]

EDIT: FIXED



Upgraded to faster internet with Bell Canada a few days ago. Gave me a new modem, Bell Giga. For years I have used my library on both the iMac or MBAir which would be picked up on my Samsung Smart TV via AppleTV 4 so I could watch videos through my iTunes on Mojave 10.14.6.
Worked for years on the older slower Bell Fibre modem.

Thought it was an AppleTV 4 issue. Have rechecked and all devices are on the new wifi network, even the ApTV4.
But no matter what I do I cannot get my iMac to recognize the TV.

I just noticed neither will it recognize my MacBookAir. About 3-4 years old, same Mojave version 10.14.6.
I was hoping i could at least use the MBAir library, to have it show up on my tv via the apple TV but nothing as well.
I had no problem getting APTV4 to recognize our 2 iPhones.
I have Bluetooth turned on in both computers so when I go into to Bluetooth, both computers say Not Connected. Here or there I have seen them connect for 1-2 seconds but disconnect again.

All i am seeing when in my system/preferences/Bluetooth are my devices listed but neither connected and a brief spinning round thing in the top right hand corner opposite where it says Devices.
Basically the same in my MacBookAir showing my TV and iMac but again, both say Not Connected.

iMac (2015 Retina 4K 27-inch). (Yes, soon to buy a new one but this one has been working perfectly this long)
MacBook Air (Retina 13-inch 2019)--again, both computers on Mojave v. 10.14.6

Don't want to upgrade the iMac any further beyond Mojave.
Guess I could on the MacBook Air but only if I knew that would fix this issue.

Can anyone possibly see something I am missing?

So it's not just the AppleTV but both iMac and Air that are not seeing one another.

EDIT: I am able to mirror my screen from the iMac to the TV but if I do that, I am unable to use my computer while my family watches the files on the TV.

 

[velocityg4]

Are you certain you are connecting to your main network and not your guest network on all devices? As their router likely supports both and both may be turned on.

 

[TohMac]

Hmmm. As far as I am aware I only have one main network. I have never, as far as I know set up a Guest Network.

All the devices are under my account, except for my husbands iPhone that is also connected.

Is there somewhere on the AppleTV I could check?

 

[TohMac]

Thanks for your help but after several days of headaches caused by trying everything I think of, I just now finally discovered that the AppleTV4 had not grabbed the new wifi network when I last looked at it. A quick reboot of the iMac and now after a week it finally works. Phew!

I should add that your comment had me look for a guest network and in doing so discovered that. I have never had to change the network settings in it before when changing my system. I guess this time it did not pick it up automatically.