If after installing the Oreo update, your Samsung Galaxy A3 (2017) randomly reboots or is stuck in bootloop, you're not alone. A significant number of users are reporting these issues after the update. Last night my phone updated to Android 8 - Oreo. And today it is unusable. It keeps restarting again and again, and again. The battery drained in less than 4 hours. It constantly freezes. I did a factory reset to check if it was linked to any of my apps, but no, even after that the issues are still there. Oreo broke my phone. I bought it less than a year ago. Curiously, some reboots are...
Source: https://www.gsmarena.com/samsung_galaxy_a3_2017_users_reporting_reboots_and_bootloops_after_oreo_update-news-31359.php