Stop the service and reset the data
sudo systemctl stop sided
cp $HOME/.side/data/priv_validator_state.json $HOME/.side/priv_validator_state.json.backup
rm -rf $HOME/.side/data
curl -L http://snapshots.liveraven.net/snapshots/testnet/side-protocol/sidechain-testnet-4_latest.tar.lz4 | tar -Ilz4 -xf - -C $HOME/.side
mv $HOME/.side/priv_validator_state.json.backup $HOME/.side/data/priv_validator_state.json
Restart the service and check the log
sudo systemctl start sided && sudo journalctl -u sided -fn 100 -o cat