Google Pixel No Wifi, No cell service like stuck in airplane mode issue

I bought a Pixel 3 about 7-8 months back and was really happy about it. Ran smoothly and everything was perfect until I came across this issue.

I'm writing this post because I couldn't find any help online much not even from Google support. So anybody else also having this issue, hope it will be helpful for you.

Issue:

No connectivity at all. No Wifi: even if you turn on/off Wifi several time, it doesn't search or connect.
No cell service: No reception, but the SIM card works if you try it with another phone.
Says the phone is in airplane mode and no radio when you try to make a call.


What happened to me and what I did

It happened a couple of times for me and the very first time, I tried network reset but it didn't work.

Settings > System > Advanced > Reset options > WiFi, mobile & Bluetooth

Then tried factory reset (wiped out all user data)
Still didn't work.

Gave up my hopes on that and thought of switching to another phone.
After 3-4 hours, found it is working again like nothing happened.

It worked great without any issues for about 2 months. Then again one time I ran out battery and it switched off itself. After charging it for sometime switched it on again. Then the same issue. No wifi, no cell service.

Tried everything again, Network reset, factory reset and even hard reset. Nothing. Finally I even downgraded the factory default android version (back to 9, earlier I had it upgraded to version 10). Nothing worked.

Then reached out to Google support.


What you should do to resolve this

I'll write the steps in the order.

1. Restart your phone
If it is a temporary glitch, it will be resolved.

2. Try network reset
Settings > System > Advanced > Reset options > WiFi, mobile & Bluetooth
This might fix your phone if it is config issue or something to do with your wifi etc.

If not,
3. Leave it aside for several hours. 24 hours max.
If it is the same issue like I had, probably it'll start to work by its own after some time.

If not,
4. Drain your phone's battery until it shuts off by itself (I figured the best way to drain it is play a video in a loop. If you don't have a video just record about a minute and let it play).
After it completely drained and when you can't start it back with the power button. Charge it in power off until fully charged and switch it on.
Hopefully it will work. If it doesn't again leave it idle for several hours.

If not,
5. Try factory reset
It should fix most of the common issues.



6. If it doesn't contact google support for pixel from the below link.
https://support.google.com/pixelphone/contact/community#

They should guide you to get you a replacement assuming it was purchased from an authorized store.

7. If you are not in a country which covers by Google support, then nothing much you can do. So the last option downgrade back to Android 9. Wouldn't recommend this if you don't know how to. You'll need some technical knowledge and some experience with android development.

8. Try with your local repair place and nothing much you can do after this. Only chance is going back to the authorized seller and try to get a replacement.



Moral of the story: 
Try to buy a product where you have support/warranty claim is available in your country, unless you really really need a Pixel phone.




References:
Pixel community forum:  https://support.google.com/pixelphone/thread/45120511
Google Factory Images:  https://developers.google.com/android/images