@walpole 

I am not sure if you have done this, but has the router been factory defaulted and all the settings left as is and tested again? Also, I was thinking what @ArcherC8 said about using those devices on a different Wi-Fi, does that work?

walpole wrote

Multiple iOS devices connected to the wifi network send and receive data fine within the browsers and in other apps (e.g., YouTube), but Instagram, Facebook, and FaceTime don't work.

@walpole 

OK, first I have iPad's and all work both using a browser and the IOS based apps. Facebook and Instagram can be used both in a browser and app and I think it is possible to do Facetime as well? And as you say, they work, so that sort of points to the app? I'd start looking on the devices at the apps. Unlikely more than one would go bad though.

A couple of things I'd suggest, more to see if it works than anything else:

• Create a GUEST NETWORK with NO SECURITY and connect to it and test.
• Delete the apps and re-install, keep the data. Possible the app needs to be updated for the iOS on the device.
• If the above fail, I'd delete the app and data too. Data could be corrupted.

One could also Google "facebook app doesn't work on iOS" as there are many hits on this.

@IrvSp 

I did disconnect the new TPLink router last night and reconnected my old ISP provided one and all the apps work again on the devices. This issue is specific to this network. I also did delete my instagram app on the old network and reinstalled and it did not work. 

@walpole 

Wow, really odd that no matter which router is there Instagram didn't work?

Sounds like 'HomeLink' could be involved, but I'd think it would be for all network connections, all bands and wired as well as wireless?

@walpole 

Just to clarify, even if the router is factory defaulted (reset held for 15 seconds), you still have the same issue?

@IrvSp I misspoke when I said "network." Those iOS apps on those devices don't work when connected to this router. When I reconnected my old router, the apps work again.

@walpole 

I'm starting to think the problem is the NETWORK CONNECTION on the devices? They 'remember' things, like MAC addresses and such. If you used the SAME SSID and PASWORD for the new router, that could be the problem. You need to DELETE those Network connections. Either that or use a DIFFERENT SSID name, which does the same thing.

Give that a try and see what happens.

Also having this issue. Already exchanged the router once, thinking it was a hardware defect and the new one does exactly the same thing. Different SSID, factory firware, updated firmware. Doesn't matter. This junker is probably getting returned and I'm going to have to try a different brand. If I plug my old router back in, all the problems magically go away.