My Asus Zenfone 3 max mobile signal disappeared after updating to Android Oreo, please help....

[ibrahimfarism]

Please tell us some basic information before asking for help:
Model Name: Asus Zenfone 3 Max ZC520TL
Firmware Version: 15.11.1810.14
Rooted or not: Not
Frequency of Occurrence: it"s been around one week
APP Name & APP Version (If your issue relates to the app): There is no
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 kcrkindia
Thank you for your asking. Kindly try some stay-at-home troubleshooting tips below:
1. Please try reset Network: Settings>System>Reset options>Reset Wi-Fi, mobile & Bluetooth
2. 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/
3. 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.
4. If the issue persists after the Factory Reset, please try SMMI test 
Calculator> type ".12345+=">SMMI TEST>Single Test>SIMCard Test/SIM Signal Test/Wi-Fi Test
If any of the SMMI tests fails, 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