Thanks for confirming that.
The next thing you will need to do is check whether the remote is sending the signal correctly or the soundbar is not receiving it correctly.
To make sure the remote is sending the command correctly, you need to make sure it is sending an IR signal when the power button is pressed and held. To do this you can use the front-facing camera on a smartphone or tablet. If you point the remote at the camera and press and hold the power button you should see a light from the end of the remote when it sends a signal.
If you don't see this light then the remote may not be sending the signal correctly, if you do the problem is from the soundbar. If it's the remote, then you will want to look at replacing the remote. If it's the soundbar, then you will want to look at getting the soundbar serviced. To do this you can reach out to your local support team and they will be able to help. You can find the contact information at this link, by selecting your country/region and then the 'Contact Us' option at the bottom of the page.
Let me know how this goes!