(Please note that this is Dutch Q&A Forum, any threads should be posted in Dutch. However, I will still provide an answer in English based on your initial response.) 

Hi, Herman De Bruyne

This usually happens because Samsung’s battery-saving features stop Microsoft Defender from running in the background. Android may then remove the accessibility permission needed for Web Protection.

Here are some suggestions you can try:

Press and hold the Microsoft Defender icon, select App info, then turn off Remove permissions if app is unused.

In App info, select Battery or App battery usage, then choose Unrestricted.

Open Settings > Battery and device care > Battery > Background usage limits > Never sleeping apps, then add Microsoft Defender.

Under More battery settings, turn off Adaptive battery. If you prefer to keep it enabled, make sure Defender is excluded from battery optimization.

Open Settings > Accessibility > Installed apps, select Microsoft Defender, and confirm that its accessibility service is enabled.

Finally, open Defender, select the Device protection or Web Protection warning card, and turn Web Protection back on.

Restart the phone afterward. If the setting still turns off daily, reinstall Defender and repeat these permissions, or contact the work administrator if the phone is managed through Intune.

Thank you for your patience in reading, I hope this information has been helpful to you. 

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