Hello @Sicog ,

Welcome to our community.

Before considering a factory reset of your iPad, there are a few things worth checking on the network side first:

1. Check your router for MAC Filtering or Access Control settings: it's possible your router has MAC Filtering or Access Control enabled, which may be blocking the iPad specifically. 
2. Power cycle your router and powerline devices: Turn off your router and all powerline devices, wait 30 seconds, then turn them back on — starting with the router first, followed by the powerline devices. Then try reconnecting the iPad.
3. Change the Wi-Fi name and password on the extender: avoiding any special characters such as apostrophes. Sometimes certain devices are more sensitive to special characters in credentials. 
4. Try connecting the iPad to a different network: (such as mobile data hotspot) to check if the iPad itself has a connectivity issue, or if the problem is isolated to this particular network.

A factory reset of the iPad would be a last resort — it's more likely a network-side setting causing the issue.