Can't make/receive calls but texts and mobile data works and with full bar of signal

[Jimwel]

1. Model Name: Zenfone 9
2. Firmware Version: Android 13 WW_33.0804.2060.142
3. Rooted or not: Not rooted
4. Frequency of Occurrence: Everytime since it started happening

For some reason, my phone suddenly can't make or receive calls. It worked fine for the last 7 months since I bought my phone (late Oct. 2022) but suddenly had this problem lately which started happening around the previous 2 weeks. The weird thing is that I actually have a full bar of signal and I can send/receive text messages just fine and use my mobile data on one of my sims (I use a dual sim and I use one of the sims exclusively for mobile data. However, I'm assuming mobile data works for the other sim as well). I'm from the Philippines so the service providers I use for my dual sim are Globe Prepaid and GOMO (for mobile data).
I've already tested the sims on another working phone, and calls work perfectly so It can't be the sim, but rather the phone itself. I already tried factory resetting the phone and even tried to make calls while volte+wifi call are on/off, to no avail. 

[Jimwel]

@Julius_Victor @dilla- I think I managed to fixed the issue. The setting that dilla mentioned seems to be a hidden setting that can only be accessed when you searched for it in the settings menu (inaccessible by simply browsing). Typing it gives you access to some other hidden settings as well (like volte). 

Take note however that toggling this setting ONLY seems to work on the sim which is set to be the default Data service network, and since i use my GOMO sim mainly for data, it is hence set to be the default Data service network, which fixed the calls issue when I initially tried it when i read dilla's reply. Realizing this, I set my Globe sim this time to be the default Data service network > searched "2g" in settings > toggled on "Allow 2G" > and now calls work again.

EDIT: Apparently it's not a hidden setting at all. Just go to Network & Internet > Internet to toggle on "Allow 2G" setting on either sim. Thanks again @dilla- 

I'm not sure if this is the best solution though given that the setting gives you a warning that it is less secure, but to be honest, I'd take that right now over a non-functional ""flagship"" phone. Hopefully this would help others who are having the same issue as well.

[dilla-]

You can choose which SIM you wanna access its settings from the "internet" page. Go to settings > network & internet > internet. Or simply from the swap down menu hold on Wifi to go there directly. It'll show both SIMS like this:

 

[Jimwel]

Ohh thanks for this. For some reason when you search the "Allow 2G" option and click the result, the settings page doesn't tell you which sim you are accessing so I assumed it was maybe a hidden setting. 

[dilla-]

I mean in my opinion this shouldn't be under "internet" in the first place that's just messy, but I'm glad I stumbled upon it. I had just accepted that I'll reset my phone.

[Julius_Victor]

So @dilla-  where have you been all this time? LOL

Thanks for sharing, mine is running perfectly fine on the latest firmware version atm!

I'm glad it worked for you too @Jimwel