Red triangle & engine stopped

Driving to work and got a red triangle and the engine stopped and I had to pull over to the curb. Pressing the start button and only getting a flash of lights on the instrumentation panel and then they go off. Pressing the start button to turn on accessories And the screen displays the battery charge screen and there are no bars on the hybrid battery charge. Battery was replaced in October 2021. It has been working extremely well since then. I have been constantly monitoring the charging status and it has been maintaining an even charge and never getting very low. Mpg has been good in the car just broke 300,000 or should I say 299,999. Been monitoring the Trip B odometer to keep track of mileage. What troubleshooting steps can be performed to identify what the problem may be? Thank you for any support!