Unfortunately, it is similar with our device. If I only want to use battery operation, there is an error message. In addition, the water jet was very visible at the beginning. Now it's just a trickle and the water barely circulates (with cable and batteries). At first I was happy about the purchase. Our cat no longer pays any attention to the fountain. The value for money is not there, which is why I advise against buying this product (despite an initially very good rating).

Use a different plug, perhaps even one with more A and replace the cable?

I've also tried changing the USB cable + plug separately but it still doesn't work, so I guess it's the cradle.

Yes, I would also advise against buying this product as it is not durable.