A tip up front, make sure that the phone has bluetooth on, and that it is not in "don't disturb" mode blocking notifications.
I have my Pixel 6 sitting on the desk next to the 66i that I just did a reset on. I open up Garmin Connect, select "more" at the bottom right, then scroll down and select "Garmin Devices". It shows my Instinct watch (connected) and both of my 66i devices (Not connected).My new 66i (the one I am working with) is GPSMAP 66i (2) with unit ID 343106xxxx. I hold on this name, a dialog pops up, and offers me to remove this device. I do! I remove this. Let's just start over. It tells me to also remove if from my phones bluetooth settings. It gives me a link to settings, I find it and tell Android to forget it.
Now I use "Add device" in the Garmin devices list screen in Garmin connect.
I use the Bluetooth screen in the 66i setup to enable bluetooth and tell it to connect. It says "waiting for phone". We wait a long time. The phone says "setup was not successful" and give me a retry button.
I get a big orange message "Instinct not supported". Well, I should think not. I find my instinct watch and move it far away into another building.
In this menu, I see "Forget phone" and select it. Now it seems eager to pair with the phone. I completely exit and reenter the devices screen in Connect and now it seems to work. Two numeric codes get exchanged. I have to type in the second one. Then it all seems to work. I skip both offers to add permissions to interact with my phone. It offers to link up and sync, that works and if offers me a Finish button. Now it wants me to install Garmin Explore. Why not? It finds this on Google play and starts the install.
I start the app. It knows my name. It finds the 66i I just activated and shows the last sync as 1 minute ago. It offers a link to Garmin Messenger. It knows about my Instinct also (but it is not in range).
Tom's backpacking pages / tom@mmto.org