Network – No Wi-Fi adapter found Ubuntu 18.04.3 Dell Vostro 5481-7273

I'm sorry for my english.

I just checked my emails and then noticed a weird symbol that I've never seen before. It was near the Wi-Fi icon. I clicked on it and it was written that it is an icon for "Location Services" and that they are off. I went to Settings, found there "location services" and there it was written, they were "in use". When I noticed that web pages were not loading, I turned off and on the Wi-Fi and found no Wi-Fi network. Then I restart the laptop, the sign for "location services" disappeared and they were now turned off in the settings and WLAN said that no wireless adapter was found.

I tried not to find the wifi adapter in Ubuntu 18.04 and could not get the wifi adapter working – clean 19.04 installation – network unclaimed

I do not know what else to post, that can help ….

sudo lshw -C network:

   description: Network controller
   product: Intel Corporation
   vendor: Intel Corporation
   physical id: 14.3
   bus info: pci@0000:00:14.3
   version: 30
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress msix bus_master cap_list
   configuration: driver=iwlwifi latency=0
   resources: irq:16 memory:a131c000-a131ffff
   description: Ethernet interface
   product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
   vendor: Realtek Semiconductor Co., Ltd.
   physical id: 0
   bus info: pci@0000:01:00.0
   logical name: enp1s0
   version: 15
   serial: e4:54:e8:0b:ee:1d
   width: 64 bits
   clock: 33MHz
   capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical
   configuration: broadcast=yes driver=r8169 latency=0 multicast=yes
   resources: irq:16 ioport:3000(size=256) memory:a1204000-a1204fff memory:a1200000-a1203fff
   description: Ethernet interface
   physical id: 2
   logical name: enp0s20f0u1
   serial: 1a:e9:9f:94:ab:ee
   capabilities: ethernet physical
   configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip= link=yes multicast=yes

rfkill list:

0: hci0: Bluetooth
Soft blocked: yes
Hard blocked: no

nmcli device show wlan0:

Error: Device 'wlan0' not found.

sudo lshw -short-class network

H/W path       Device       Class          Description
/0/100/14.3                 network        Intel Corporation
/0/100/1d/0    enp1s0       network        RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
/2             enp0s20f0u1  network        Ethernet interface