Recently VoWiFi stopped working for Telstra/Boost Australia

[noldoli]

Please tell us some basic information before asking for help:
Model Name: ROG 5
Firmware Version: WW-31.0810.1226.139
Rooted or not: Not rooted
Frequency of Occurrence: Always
APP Name & APP Version (If your issue relates to the app): Phone calls
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.
========================================
For almost a year (from ~Nov 2021 till ~Oct 2022 or so this year), with Australian mobile carrier Telstra (and by extension its retail MNVO, Boost), ROG 5 used to work very well with VoWiFi (aka WiFi calling). Then recently, it's stopped working. (VoLTE still works though; so the problem is limited to VoWiFi only at this stage.)
Can this problem be fixed ASAP please? This is an essential functionality of a phone for me.
Living in an outer suburb with terrible mobile signal coverage inside home, this is causing me grief (in terms of mobile call quality being terrible and unreliable). When VoWiFi was working, due to being connected to strong WiFi network based on a fast/reliable fibre Internet connectivity, phone calls inside the home used to be always great. But not anymore!
I've proven that the SIM itself delivers VoWiFi on a Motorola Moto G 5G phone. So SIM and mobile operator are clear in this case.
(I'm asking around for Optus & Vodafone-TPG SIMs to see whether this VoWiFi breakage is limited to Telstra.)

[noldoli]

Tested with Optus. It works for VoWiFi. But VoWiFi doesn't work for Boost & Telstra.
It used to work for months, perhaps it got blacklisted recently.
There goes my consideration of ASUS for future purchases.

[keren_ASUS]

HI noldoli
Thank you for letting us know about this. Can you help us out and provide a log + video so our team can analyze the situation.
Please follow the below steps to enable the built-in log tool (Bug reporter).
1.  Open “Calculator APP”
2.  Enter “.19595+=”
3.  Select the Log type according to the type of issue you want to capture. “General cases” will work for most issues but you can find a list further down explaining each option in more detail.
4.  After your selection the log tool will exit so you can duplicate the issue or wait for it to happen. Try to use the screen recorder to show your issue when possible. If you can't screen record your issue, then please take a screenshot right after the issue has occurred (as a timestamp) so we know where to look in the log.
5.  Navigate back to the log tool via calculator and Tap "FINISH AND SHARE".
6. It takes several minutes for the log to generate. You can exit and do other stuff in the meantime. A silent notification will tell you once the process is done. Tap the notification and then the share button to upload the file to Google Drive and share the link with a moderator. Just make sure to change the permission first so that everyone with the link has permission to view it.
Note: When you're no longer planning on logging your device, enter “.09595+=” in the calculator and the log tool will stop as well as deleting all stored logfiles. Make sure to share via calculator. The files found in internal storage -> asus_log are not the correct files (they are only 1.2kb)
Which log type to use?
General cases = Issues with the UI and most general strange behavior in system or app
Phone, mobile networks and signal = Issues with phone calls or cell reception
Wi-Fi = Any issue where you have issues with your Wi-Fi
Bluetooth = Any issue involving bluetooth
Location = GPS issues
Sound, call audio and recording = If you experience issues with any type of sound quality

[noldoli]

Hey @keren_ASUS, first of all thank you very much for trying to help. Alas, I'm currently in an overseas destination. However, I'll be back in Australia round 6th Jan. Then I'll follow those steps you've listed & report its findings here. Please stay tuned. Once again, thank you for your help.

[noldoli]

Hi @keren_ASUS , I've captured the "Phone, mobile networks, and signal" logs & uploaded it to Google Drive. (Captured it during my attempt to activate WiFi-calling) If you can send me a DM, I'll send you the link. Thanks