Hotspot not working after update to Android 7.0 (Xperia Z5 Premium Dual)

[OBATUS]

2 weeks ago my 2-month old Z5 Premium Dual updated itself to Android 7.0.  Ever since, my hotspot (which I need to use everyday) stopped working properly.  You can reach the internet just fine, directly from the phone; but there's no internet on connected laptop (which connects without a problem) when you activate the hotspot (the internet still works just fine on the phone, even when the hotspot is on).

I have two SIMs, both with data packages.  Someone mentioned something about disabling the second SIM, but that did not help.  Sony customer service recommended I do a software repair, which cost me almost a full day.  Unfortunately, nothing changed.

I run Windows Network Diagnostics and get the "Your DNS server might be unavailable" message when I disable or remove SIM2; and get the "Your broadband modem is experiencing connectivity issues" message when I leave the SIM2 in and active, or locate SIM1 in SIM2 slot.  So, it's not a question of having two SIMs with active data packages.

This is very frustrating.  Until the update, same laptop used to connect to the internet through the same phone's hotspot (with the same two SIMs and data packages) without any problems.  Somebody please help, otherwise I will have to dump this very disappointing phone and go back to Samsung very soon.

Thanks!

[Odeira · Accepted solution]

You could try this. It's worked for so many folks, all the way back from Kitkat, apparently.

From https://pmf.silvrback.com/fixing-tethering-on-android-kitkat

Via https://forum.xda-developers.com/z3/general/lollipop-tethering-t3058923

1. Enable developer mode (Go to Settings -> About phone, and click on the build number until the developer mode is enabled).
2. Enable USB debugging under Settings -> Developer options
3. Connect the device with a USB cable to a computer with the Android SDK platform tools installed
4. Start an adb shell: adb shell
5. In the adb shell, run this command: settings put global tether_dun_required 0

Similarly, you could try removing the hotspot password and hoping no one else devious will connect to your device. But PLEASE try the ADB fix before you go to a Samsung. I'm writing this very comment from my fixed hotspot tethering on my Z5 Premium (single sim) as we speak!!!

[OBATUS]

Aaahhh, finally!  Thanks a gazillion Odeira.  Your quick help is appreciated very very much.  :smileysmileythumbsup:

[LegendaryLionMa]

This works! I have a Oneplus 3 and solved the same problem with it! Awesome!

[Odeira]

I always suspected it was an Android deficiency more than anything. I'm glad that was fixed on your OnePlus 3...

[b41]

Thank you very much, i'm not even a phone guy but i did it myself with your explanation and this videos help. 

       This video shows you how to do 3. step (no relativity with this youtuber btw).

                 https://www.youtube.com/watch?v=qhYnHsmuJfo

And if you' ll not understand step 4 - Start an adb shell - (like me), it means that you have to run command: ./adb shell  -on terminal.

After that enter this command: settings put global tether_dun_required 0