Hello MrsFrantz967,
With multiple devices all having the same issue, we would suggest you look at the router/modem involved.
Even if some devices are working fine, it is very possible for a router to have an issue with other devices. This can usually be resolved be restarting all the components involved. Turn the power off on the router/modem for at lest 60 secs, then power it back on. At the same time, power the Apple devices off. When the router/modem is back up, and connected to the internet, restart the Apple devices and see if the problem continues.
If the problem remains, the next step would be to test the device having an issue on another network and see if the issue remains. This will help you isolate the problem to the device, or the network equipment.
Once you have that information, you will know where to concentrate troubleshooting efforts.
Have a good day.