why did all my series x controllers suddenly disconnect and refuse to pair up again?

Hi PapiKinder!

Sorry to hear about the issue. To further isolate it, please try to connect your controller using a USB cable if they worked fine when connected hard-wired. If they worked, try to check for controller updates.

If you could navigate through the dashboard or system menu, I suggest that we perform a factory reset on your console to refresh its system and remove potentially corrupted data in it.

Press the Xbox button to open the guide.
Select Profile & system > Settings > System > Console info.
Select Reset console.
On the Reset your console? Please choose “Reset and keep my games & apps”

Your solution wasn't my problem,

but a microsoft techie told me via chat to hold power and eject at same time and power on, before i was able to do the chat disconnected.

I did what was asked anyway and when system started all controllers were operable.

This technique is the solution for problem i stated above with all my controllers rendered inoperable after being paired with series x console.

This happen to me before. All i did was recover my account again and it suddenly worked like a charm and never got disconnected when starting up a game.

It takes time to test.

First, I turn my controller off then hold 10-15s sync button to reset

Then, I unpair and re-pair as your suggestion

My controller is good so far.

Edit: My controller suddenly has xbox button blink and disconnect then re-connect AGAIN.

Everything can't solve this issue. Battery is 30%

Xbox Series X. And yes, I paired it up again but still only changed the volume by one step.