In order for us to help you with your question, please provide us a minimal reproducible example where you provide a minimal (dummy) dataset and code that can recreate the issue. Once we have that, we can go from there. For help on creating a Reprex, see this guide:
A screenshot is not useful as we cannot copy paste any of the data, furthermore, you have provided no details on what time series you are talking about. Are you trying to just plot glucose, are you building a prediction model, ...