Lost coins

Hi,
I had Ardr coins on a the ardor lite wallet.
I just noticed the coins were transfered in december 2022. I do not remember of this transfer and wonder what happened.
Any suggestion is welcome.
Thanx

hi. what is your account (ARDOR-)?

account: 3978419513315319883
Payment was
from ARDOR-AS4D-H23C-4JMT-5HKFG (me) to ARDOR-5TSU-BRTV-6DBT-FRTM2

The question is what is account ARDOR-5TSU-BRTV-6DBT-FRTM2?

You have not completed the outgoing transaction and your 64-bit key has been hacked. There is always a warning in the wallet interface.

Thank you.
How do you see my private key has been hacked?
How is it possible?
Finally the coins were safer on the exchange than on the wallet…