Users can reactivate their expired SIM cards independently online or by visiting the nearest mobile operator's office.

Select SIM card manager. Choose your SIM (If you only have a physical SIM, it'll just be the only one listed). Tap Convert to eSIM. Follow the on-screen instructions and then you're done.

Restarting is always a good fallback, but before you get to that point, there are other steps you can take if you're off the ...