The problem

I have an issue connecting to the wifi on a fresh install of Lubuntu 20.04 on
my lenovo laptop. I have a RTL8723BE PCIe Wireless Network Adapter.

At my friends house I have no trouble connecting to their wifi.

At my house, I can see all the networks (and mine has full signal strength) but
when I enter my password to connect, I just get a message from the nm-tray
saying "Connection lost, No longer connected to 802-11 wireless..."

What I have tried (without any success)

I plugged the live Lubuntu usb into my other pc (which usually runs Ubuntu
18.04, and has no problems with connecting to the wifi, with Network controller: Broadcom Inc. and subsidiaries Device 43c3 (rev 04)) and booted
from Lubuntu and still couldn't connect to the wifi. This is the same when I
plug the usb into the laptop and booted from it - also couldn't connect. So I
guess it's not hardware specific...

On the laptop I have tried the following (rebooting in between any changes):

• Changing the band from 'Automatic' to 2.4GHz

  
  



• Selecting Channels 1,6, or 9

  
  



• Changing IPv4 Method from 'Automatic DHCP' to 'Automatic DHCP (addresses only)'

  
  



• Changing from 'WPA & WPA2 Personal' to 'LEAP'

  
  

cat /etc/modprobe.d/rtl8723be.conf

options rtl8723be ant_sel=1

cat /etc/modprobe.d/rtl8723be.conf

options rtl8723be ant_sel=2

sudo nmcli networking off

sudo nmcli networking on

sudo modprobe -r rtl8723be

sudo modprobe rtl8723be

Useful info from running some commands

sudo lshw -C network

  *-network

       description: Wireless interface

       product: RTL8723BE PCIe Wireless Network Adapter

       vendor: Realtek Semiconductor Co., Ltd.

       physical id: 0

       bus info: pci@0000:09:00.0

       logical name: wlp9s0

       version: 00

       serial: b0:10:41:c8:d9:e5

       width: 64 bits

       clock: 33MHz

       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless

       configuration: broadcast=yes driver=rtl8723be driverversion=5.11.0-25-generic firmware=N/A latency=0 link=no multicast=yes wireless=IEEE 802.11

       resources: irq:19 ioport:3000(size=256) memory:b2400000-b2403fff

sudo lspci

09:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter