Troubleshooting method:
1. Turn on the phone settings, and click Password & security;
2. On this page, select System security and click the Credential storage option;
3. Find the Trusted certificates and click it;
4. Turn on the switch on the right of the option you want to enable;
5. If it cannot be restored, please back up the data and reset the factory settings.
If the above operation is invalid, please bring the purchase certificate to the realme service center for tesating.