So I have 46 IOT devices connected at home and at around 32 items I found I was unable to connect more of them.
After some serious troubleshooting I discovered that the router has a limitation on the “Clients Name” field. The client names for some of my items were exceedingly long such as:
My LifX globes also had long names in the router and by chance I discovered that the router had reached its limit for that one field and would not allow any new connections.
I shortened all of my device names to just a few characters such as Sonos, Lifx, Wyze, Wemo etc because it made no difference to the device apps at all and now I can connect new devices without issue.
I reported this to ASUS as well…but I thought in case you have issues its another path to troubleshoot down.