Can't sign in to Fox News comments on iPad/iPhone

Therein lies your likely problem...

If you have a VPN App or profiles installed, or a security App such as Norton, these may be interfering with your iPad's network connection. Norton (and similar security Apps) will install a network proxy - through which your network traffic will be routed. This proxy connection can [and often does] cause issues.

Disabling or completely removing VPN or the offending security App may be necessary - followed by a device restart - to restore normal connectivity. If this resolves your issue, it may then be possible to reinstall the VPN or security App.

If you continue to have difficulties, check to see if your iPad is using the new WiFi Private Address feature. This feature is intended to provide additional privacy and security when using “public” (untrusted) WiFi networks.

Settings > WiFi > [Your WiFi Network / SSID] - tap the “i” icon - Private Address

The Private Address feature is largely unnecessary for your home WiFi network; if enabled, Private Addressing can cause issues if specific MAC addresses are expected by your WiFi Router. You may need to disable this feature - and can be enabled or disabled for each individual network.

Use private Wi-Fi addresses in iOS 14, iPadOS 14, and watchOS 7 - Apple Support

Any VPN software involved? We are seeing a rash of issues with client-side VPNs. Unless issued by an employer to allow access to their servers from an employee's remote device, most of the ones overhyped on TV are problem-causing rubbish.

Useless anti-virus is also a common cous eto connec tio issues.