Anti-theft system was tripped -- how did you unlock the door? If you do not use the driver's door key cylinder or remote control to unlock door, you could set off the anti-theft system.
RepairPal Certified shops can diagnose and repair your 2017 Kia Optima. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
It's possible your battery may be bad if there is a change in voltage drop the computer it triggers the alarm