Let me jump to the conclusion first.  Likely, you are having the "flashing blue light" problem with your Asus router, and are looking for a solution.  I know it is frustrating and you just want it fixed!  So here is what I did.  You can read on for the details, and I also ask that you consider subscribing to my blog or following me for my tech articles and astrophotography!

To fix my Asus ZenWiFi AX node not connecting to my router, indicated by a flashing blue light, I simply powered off the router and then turned it back on.  Once the router was fully back, the node re-connected shortly thereafter.

Obviously this is no guarantee of a fix for your particular router/mesh issue, but it is a prudent troubleshooting action to power-cycle the relevant devices.

Recently, I decided to upgrade my home WiFi from a LinkSys AC router, which I used for about six years.  It was very reliable, but had been starting to show signs of stress due to new demands (e.g. security cameras) that I placed on my private network.

After a short tour of exploring options, I bought the Asus ZenWiFi AX mesh 2-pack.  At the highest level, I can say the setup went amazingly smooth, including a firmware update on both the router and node.  The instructions were simple and using the Asus Router app for iOS was straightforward.  It actually seemed almost too easy.

A couple of days after the setup, I decided to move the node slightly, noting that until this point, I had not powered off either the router or node since I completed my home WiFi transfer/setup to the new devices.  To move the node, about five feet, I powered it off so I could reconfigure the cables.  When I turn the satellite node back on, after pulsating green lights (normal), the LED started flashing blue, not the stable white light I was expecting!  The node was not connecting back to the router, as indicated within the Asus Router app.

At this stage, I should have realized, as an IT person, to try "rebooting," not just the node, but the router as well.  I performed multiple restarts and resets of the router, but the flashing blue light always returned.  Specifically, there was a looping light pattern:

Power On -> Pulsing Green -> Steady Blue -> White (~1 sec) -> No Light -> Pulsing Green -> Flashing Blue -> White (~1 sec) -> No Light -> Repeats Sequence with Pulsing Green Again

I decided, for the heck of it, to restart the router, by powering it off, waiting about 10 seconds, and then turning it back on.  After the router went through its setup and was online, indicated by a steady white light, I checked the still-on node to see that its light had resumed being steady white as well!  In truth I do not know how long it took the node to finally reconnect after the router reboot, but it could not have been more than two minutes.

Interestingly, as part of the node troubleshooting, I removed the node from the Asus Router iOS app, so that my WiFi system was only showing the single router with no satellite node.  When the node's light turned stead white again, the node re-appeared in the app, without any intervention on my part.

Here is my guess as to what happened:

The firmware upgrade caused a change in the restart/reconnect process from node to router.  Since I had not rebooted the router since the firmware update, the router was still using the "old" connect protocol from the prior firmware, but the node, after its reboot, was trying to connect to the router with the new protocol from the latest firmware.  After the router rebooted, the router activated the new protocol and everything was fine.

If you have questions about my troubleshooting process for my Asus mesh WiFi, please leave a comment below!