Set your cellphone to safe mode.
1. Shut phone down
2. Hold volume up and power button at the same time for a few seconds until safe mode screen pops up
3. "Wipe cache partition", then select "Repair Apps".
After that, open settings app, enable developer options. Once enabled, open it, then enable "Force 4x MSAA", "Disable HW overlays"; lastly, set "Background process limit" to (4)