Hello Pinkal,
Thank you for your question and for reaching out with your question today.
The error indicates that the power passthrough output from these speakers is insufficient to effectively charge your Surface. You will need to connect the surface to a charger separately from the speakers in order to charge it and not receive the error message. Please continue using the standard power supply of the Surface Pro for now to charge the device. THis is a known issue and Microsoft have been reportedly looking into it.
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Best regards.