iPad WiFi works for some apps but not others

Last item first, for iPad Air2, iPadOS 15.7.5 is current. You should update your iPad to this version as soon a practicable - as this version includes essential system security updates.

From your description, your iPad has a problem with its internal routing table. The potential causes are many, but are usually attributable to some types of App or associated device configuration.

If you have a VPN App or profiles installed, or a security App such as Norton, these may be the cause of the problem. In such circumstances, the resolution is usually relatively simple; if installed, you may only need to temporarily remove the Security App and/or VPN - and then perform a forced restart of your iPad.

If installed, the Norton App is almost certain to be the cause. Permanent deletion might be the best avenue… 🙂

Norton, like similar “security” Apps, installs a local network proxy. This proxy modifies the local routing table - often to unpredictable and unreliable effect.

You are very welcome.

Having cleared the problem, you should be able to reinstall Norton should you choose to do so. If the problem returns at a later date, you’ll know what you need to do.

As for benefits of Norton, perhaps consider that the iOS/iPadOS sandboxed security architecture is designed to isolate Apps from each other - each App only being able to access its own private storage and assigned system resources. This intended separation prevents Apps from accessing storage and resources of other Apps; for traditional security Apps, this presents a fundamental problem.

To work-around this limitation, Norton installs a network proxy, which attempts to reroute and examine your network traffic. In some instances, as here, the proxy disrupts expected network traffic routing - if not completely interrupting the network connection, selectively dropping traffic for some Apps - as you appear to have experienced.