Solution:
When connecting multiple devices, since the earbuds can only be connected and interacted with one Xiaomi Earbuds app , if the earbuds have been connected to a mobile phone, the connection cannot be made through the Xiaomi Earbuds app in another mobile phone, and a connection will be prompted fail. If you want to connect with two devices, it is recommended to search for the headset through the MIUI phone pop-up window or through the Bluetooth interface to connect.
Does it help?