WiFI using Realtek RTL8812AU not found (Ubuntu 16.04.3 LTS) - ubuntu-16.04

Question

Currently I can't use Wifi on my Ubuntu 16.04.3 LTS. However same hardware works, when booting Win10, or using Ethernet on Ubuntu.
When setting up the machine (desktop and external wifi adapter) I did lsusb and recieved following information:
Bus 001 Device 006: ID 0bda:8812 Realtek Semiconductor Corp. RTL8812AU 802.11a/b/g/n/ac WLAN Adapter
So i used following tutorial to set it up using ethernet connection. It worked fine, with the same speed as on all other machines. I can't recall changing anything, what could have triggered this issue now. rfkill unblock all isn't helping.
Current information:
cat /etc/lsb-release provides
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04.3 LTS"
lshw -C network provides
*-network
description: Ethernet interface
product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
vendor: Realtek Semiconductor Co., Ltd.
physical id: 0
bus info: pci#0000:03:00.0
logical name: enp3s0
version: 15
serial: 10:7b:44:17:66:c2
size: 10Mbit/s
capacity: 1Gbit/s
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation
configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half firmware=rtl8168h-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=MII speed=10Mbit/s
resources: irq:128 ioport:d000(size=256) memory:f7204000-f7204fff memory:f7200000-f7203fff
uname -r provides
4.10.0-38-generic
lspci -k provides
00:00.0 Host bridge: Intel Corporation Device 591f (rev 05)
Subsystem: ASUSTeK Computer Inc. Device 8694
00:01.0 PCI bridge: Intel Corporation Sky Lake PCIe Controller (x16) (rev 05)
Kernel driver in use: pcieport
Kernel modules: shpchp
00:14.0 USB controller: Intel Corporation Sunrise Point-H USB 3.0 xHCI Controller (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H USB 3.0 xHCI Controller
Kernel driver in use: xhci_hcd
00:16.0 Communication controller: Intel Corporation Sunrise Point-H CSME HECI #1 (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H CSME HECI
Kernel driver in use: mei_me
Kernel modules: mei_me
00:17.0 SATA controller: Intel Corporation Sunrise Point-H SATA controller [AHCI mode] (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H SATA controller [AHCI mode]
Kernel driver in use: ahci
Kernel modules: ahci
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #5 (rev f1)
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1c.7 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #8 (rev f1)
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1d.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #9 (rev f1)
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1f.0 ISA bridge: Intel Corporation Sunrise Point-H LPC Controller (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H LPC Controller
00:1f.2 Memory controller: Intel Corporation Sunrise Point-H PMC (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H PMC
00:1f.3 Audio device: Intel Corporation Sunrise Point-H HD Audio (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H HD Audio
Kernel driver in use: snd_hda_intel
Kernel modules: snd_hda_intel
00:1f.4 SMBus: Intel Corporation Sunrise Point-H SMBus (rev 31)
Subsystem: ASUSTeK Computer Inc. Sunrise Point-H SMBus
Kernel modules: i2c_i801
01:00.0 VGA compatible controller: NVIDIA Corporation Device 1c82 (rev a1)
Subsystem: ASUSTeK Computer Inc. Device 85d3
Kernel driver in use: nouveau
Kernel modules: nvidiafb, nouveau
01:00.1 Audio device: NVIDIA Corporation Device 0fb9 (rev a1)
Subsystem: ASUSTeK Computer Inc. Device 85d3
Kernel driver in use: snd_hda_intel
Kernel modules: snd_hda_intel
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
Subsystem: ASUSTeK Computer Inc. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
Kernel driver in use: r8169
Kernel modules: r8169
04:00.0 USB controller: ASMedia Technology Inc. ASM1142 USB 3.1 Host Controller
Subsystem: ASUSTeK Computer Inc. ASM1142 USB 3.1 Host Controller
Kernel driver in use: xhci_hcd

Answer 1

RTL8812AU is not included in the "base" Ubuntu. You would need to download and compile the module manually. You can try:
sudo apt-get install linux-headers-generic build-essential git
git clone https://github.com/scrivy/rtl8812AU_8821AU_linux.git
cd rtl8812AU_8821AU_linux
make
sudo make install
sudo modprobe 8812au