@SamUK What's the model No. of your extender? RE200, or 850RE? Please Reset extender, then login to it, and go to"Setting--> Wireless-> Connect to Network" to setup this extender.

Please check the Link speed on your PC when connect to RE205 wifi. It's 433Mbps on 5G wifi?

@KyleW What's the model NO. of your extender? RE200, or TL-WA850RE? Please check this post: Has connected to TP-Link extender but no internet, what can I do?

Normally, regardless the number of client devices, with extender in your network will not affect the speed of your router. Extender is mostly used to extend the wifi range. "Thus, in order to lessen...

To hack the extender or any other devices, it's necessary for the hacker to access to your network. That's the priority we should avoid. Here are some suggestion for this. 1. Please set strong wifi...

@LuisR Normally, this won't cause the configuration loss issue. This may be an accidental. Please reconfigure RE450: 1. Tether APP: How to configure Range Extender via Tether APP 2. Web UI: How to...