1.Check that you have a good network connection.
2.Go to [Settings]> [Additional setting]> [Date&Time] and enable [Set Automatically]. Google Play Services sync with their master servers to send and receive data, to do this your device time and date should be correctly set.
3. Go to [Settings] > [App management] > [App List] > Click on two vertical dots in top right corner > [Show System] > Scroll Down to [Download Manager] > tap on [Enable] to enable the app.
4. Go to [Settings] > [App management] > [App List] > [Google Play Store] > [Storage Usage] > clear data and cache.
5.If the issue still persists, try to remove and add your Google Account on your device.
Source: Realme