AMS will not change over to new coil with same wire

For the first time I could in practice test the change over of the coils from A1 to A2, but it would not do it.
I had 2 coils with the same Bambu wire, type and color installed, and had only a few meters on A1. I started the print with A1,
All went well until the A1 was empty and the wire went through the feeder well, then that LED went red.
So far so good, but then the machine parked, and would not continue; on the PC I saw that it did not plan to continue printing as there was a message that the slot A1 needed to be refilled. I could not do anything else but just that, then the machine restarted and finished the print. I show a few pictures of the process, and wonder what , if anything, I had missed out.
Edit:

I am new here… so take lightly

On the X1c
I needed to go to the settings and tik
the box allowing " ams filament backup".

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