[RT-AC86U] Lost connection to smart home devices, can't reconnect

Hi! I recently hooked up a new RT-AC86U, and everything is great. I have Smart Connect enabled, and I've attached two smart bulbs and one smart plug to the network. They only work on the 2.4 GHz band, but they got set up and were functioning fine. I had to pair them to my phone through the Smart Life app, but that worked fine despite the fact that my phone was running on the 5GHz band at the time (at least I assume it was - it always has been when I've checked).

Last week, I went away for...

[RT-AC86U] Lost connection to smart home devices, can't reconnect