My Asus zenfone 5z bottom speaker is not working on video calls.

[Shyste]

Please tell us some basic information before asking for help:
Model Name: Asus Zenfone 5z ZE620KL
Firmware Version:cant locate
Rooted or not:not
Frequency of Occurrence:just now
APP Name & APP Version (If your issue relates to the app): messenger version 283.0.0.16.120
In addition to information above, please also provide as much details as you can, e.g., using scenario, what troubleshooting you've already done, screenshot, etc.
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[Christine_ASUS]

Hi Shyste
Thank you for your asking. Kindly provide the information below so that we can better assist you.
1. Your current firmware version
Settings>System>About Phone>Software information
If you try to update to the latest version, does the issue still persist?
2. Can't the speaker work in Messenger only, or does the issue appear in other apps, video playing as well?
3. Please check on SMMI test 
Calculator> type ".12345+=">SMMI TEST>Single Test>Speaker Test
If any of the SMMI tests 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
4. Please try to enter "Safe Mode". If the function works well in Safe Mode yet the issue remains out of Safe Mode, please check on any disturbance from the installed 3rd party apps.
# How to enter and exit "Safe Mode"
https://www.asus.com/support/FAQ/1005163/
5. Also, please try "the Factory Reset" 
Settings>System>Reset options>Erase all data(factory reset)
Please note that once the Factory Reset is completed, all data, apps, settings and personal information will be deleted.