cannot connect to smart power strip (TP-link-Kasa, KP303)

it's a firmware issue.. definitely not an issue with the power strips.. I have the exact same power strips and the exact same model of router (RAX40)... I had the same issues with router firmware version 1.0.3.80 and when I was able to get a firmware update, the update fixed the issue. Mine was a beta firmware but there is a public version (which may have some functionality stripped because that's how terrible Netgear are), but it may solve your issues regarding the power strip causing the router to completely crash. linke to v1.0.3.88 firmware: https://kb.netgear.com/en_US/000062596/

Christian_R  I'd suggest not straight away considering that it's the fault of the product we're trying to connect to the router, and consider the router itself is faulty. There have been a sleuth of issues reported against the RAX40 and to turn a blind eye to all of them is downright shady.. If you recall a few months back I reported this exact same issue (along with a lot of other issues that 99% of the other RAX40 owners are having)