Hi
ultimo32Thank you for your asking. Kindly provide the information below so that we can better assist you.
1. Please try reset Network: Settings>System>Advanced>Reset options>Reset Wi-Fi, mobile & Bluetooth
2. Have you tried the Factory Reset? Does the situation remain the same?
Settings>System>Advanced>Reset options>Erase all data(factory reset)
Please note that once the Factory Reset is completed, all data, apps, settings and personal information will be deleted.
3. Can other SIM cards work properly in your device?
4. Did the issue only be triggered by Whatsapp?