Back and recent button isn't working

[faymeeldhie]

Please tell us some basic information before asking for help:
Model Name: ASUS_X00ID
Firmware Version: ww_zc554kl_15.2016.1907.519_20190724
Rooted or not: NOT
Frequency of Occurrence: a week
I've been struggling with this issue for over a week from now. I have tried the suggested safe mode and factory reset but it still won't work. Do you have any advise why are these happening? This issue was just occurred in a sudden.

[Christine_ASUS]

Hi faymeeldhie
Thank you for your asking. Does the issue only appear in specific panel (back and recent area)?
Please try the following steps to access recovery mode for the Factory Reset:
0. Try to back up your data with USB cable. If you can not access the phone, please check if your google account or microSD card have auto backup your data. 
1. Power off the phone, then keep pressing "volume down key"
2. Press "power key" and stop press " power key" once you feel the vibration. Still keep pressing "volume down key".
3. Stop press "volume down key" once you enter [Android Recovery] Screen
4. Choose "Wipe data/factory reset">"Yes"
5. "Reboot system now"
#Hardware Reset Guide
https://www.asus.com/support/FAQ/1006346/
Please note that once the steps are completed, all data, apps, settings and personal information will be deleted.

And check on SMMI test 
Calculator> type ".12345+=">SMMI TEST>Single Test>Display Test, tap back and recent area.
If the SMMI test fails, indicating high possibility of faulty hardware, kindly bring your device to the nearest ASUS repair center for device checking: https://www.asus.com/support/Service-Center-All-Countries/
If it is impossible to access the service center during Covid-19 period, please try Call us: https://www.asus.com/support/CallUs