All Reolink products except for the battery-powered cameras.
When users are changing the Resolution settings for the cameras, this error occurs.
Below is the reason why you are unable to change it.
Before you use the Reolink Client/App to change the resolution settings, please kindly confirm whether you had added the camera to the third-party software or NAS.
If you have set the camera via that software, it will prevent the resolution changes.
You could delete the camera from that software, then reconfigure the settings you want via the Reolink Client.
Or the easier way is to restore the camera to factory settings, then the resolution change will work.