Safe Mode puts your phone in a diagnostic state (returned to default settings) so you can determine if a third-party app is causing your device to freeze, reset or run slow.
With device powered down, press and hold the Power button until the LG logo appears then release.
With the LG logo still onscreen, press and hold the Volume down button (located on the left-edge of the device).
Continue to hold Volume down button until "Safe mode" appears in the lower-left of the unlock screen then release.
The process may take up to 45 seconds to complete.
With Safe Mode enabled, test device and app functionality. If the previous issue fails to occur, the cause has been isolated to a third-party app and all recently installed or updated apps should be uninstalled.
Power cycle the device to disable Safe Mode, reinstall then test each app, one at a time, to identify which is causing the problem.