Answer: Hi there, today Mytour.vn will address your inquiry. The issue of iPhone auto-restarting is a common problem not only limited to the iPhone 6 Plus model. There are various factors causing this problem, which can be quite troublesome for users. To address the iPhone 6 Plus automatic restart issue, you can consider one of the following solutions:
Toggle Mobile Data On/Off
When encountering the iPhone 6 Plus auto-restart issue, the first thing you can try is toggling the mobile data on and off by navigating to Settings → Cellular/Mobile → Turn On/Off Mobile Data.
Restarting an iPhone 6 is quite simple: just press and hold the power button and the home button simultaneously for a few seconds until the startup logo appears on the screen, then release both buttons.
Reset iPhone 6 Plus
Access Settings → General → Reset → Reset All Settings
Restore from an Old Backup
You can connect your iPhone 6 Plus to iTunes on your computer and restore from an old backup. This is also a solution that many people have tried and succeeded with.
Fix App Errors
In many cases, continuous iPhone 6 Plus restarts are caused by conflicting apps or system errors. In this situation, simply locate and delete the problematic app, then restart your device.
Restore iPhone
To do this: Press and hold the power + home buttons until the screen goes blank. Then connect your iPhone to your computer's iTunes and restore iPhone.
Replace iPhone Battery
https://Mytour.vn/troubleshoot-iphone-6-plus-auto-restart-2497n.aspx
Replacing the battery on your iPhone is also an option if the above methods are unsuccessful. However, for the best iPhone 6 Plus battery replacement, it's advisable to take your phone to a reputable and quality repair shop.