Message at startup 'Tous les paramètres ont été réinitialisés aux valeurs par défaut'

Hello, I have a problem that started when I changed my screen. I switched from my computer monitor to my living room TV because I live in a small studio. Anyway, the TV did not detect my computer. After several restarts, it worked, and when the image was transmitted from my PC to my TV, a message appeared saying that my settings had been reset to default. I have the choice to press either F1, which takes me to the BIOS, or F2, which starts the computer. You might say, “Just press F2, it’s not a big deal.” The problem is that the date and time have been reset, and some notifications like internet access or my antivirus don't appear at the first boot after that message. So I go to start and request a restart, and then everything works except for the date, which has been reset to 2013. I have no idea why. o.o Please help me fix this problem!

Configuration: iPhone / Safari 11.0