OnePlus
Add App to Data Saver Exception List auf OnePlus
Data Saver on OnePlus phones limits background data for every app that is not explicitly marked as unrestricted. This affects messenger apps like WhatsApp the most, since they rely on a constant background connection to fetch new messages instantly.
When Data Saver blocks that connection, notifications only arrive once you open the app manually, which feels like delayed or missing messages.
To fix this, add the affected app to the unrestricted data list. Open Open the Settings ➔ Tap on Wi-Fi & network ➔ Tap on SIM & network ➔ Tap on Data Saver ➔ Tap on Unrestricted data ➔ Set the desired apps to unrestricted data usage.
Only enable this for apps that genuinely need background data, since every exception increases mobile data usage on your plan. Turning off Data Saver entirely removes the restriction for every app, but it also removes the battery and data savings the feature provides.