Is there any text alongside the code describing the error?
What are you doing when you get this error message? Is it when accessing live view, playback, or event notifications?
Do you have a screenshot of the error message?
Has playback worked in the past and only just stopped working or is this the first time you've tried to access playback?
If it has worked in the past, are you aware of any changes you've made to the system since playback last worked for you?
Is this just a single camera recording to a MicroSD card or is it connected to an NVR? Can you give us the model numbers of the cameras/NVR that you have?