SmartThings error 31-164 of air conditioner

My air conditioner (3,5 kW AR12KSWSBWKNZE) always shows offline.

I removed it and tried to add it again.
Registration also gives error code 31-164 on both the iPhone 12 Pro and Samsung S20 FE.

On one occasion the tooltip said it might not be mine on the device.

I wrote to support, but they don’t respond
Thank you in advance!