How to fix error "Connection lost" in desktop app
Seeing a “Connection lost” error? This fix usually solves it in a couple of minutes. You only need to add one line to your device’s hosts file.
Pick your OS below and follow the troubleshooting steps.

Make sure that you have admin rights on your device.
Windows
Option 1: use Command Prompt
- Open the Start menu and look for Command Prompt (
cmd.exe) - Right-click → “Run as administrator”
- Type the following command:
echo 127.0.0.1 launcher.mlx.yt >> %SystemRoot%\System32\drivers\etc\hosts - Press Enter
Option 2: edit the hosts file manually
- Go to the
hostsfile directory:C:\Windows\System32\drivers\etc\hosts - Open the
hostsfile as an admin (right-click → “Run as administrator”) - Check if the file contains the following line. If the line is missing – add it:
127.0.0.1 launcher.mlx.yt - Save and close the file
Before you continue, clear your DNS cache. It can help the app connect more smoothly. Follow these steps:
- Open the Start menu and look for Command Prompt (
cmd.exe) - Right-click → “Run as administrator”
- Type the following command:
ipconfig /flushdns - Press Enter
- Relaunch the app
The hosts file should look like this:
File reference
# Copyright (c) 1993-2009 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
# 102.54.94.97 rhino.acme.com # source server
# 38.25.63.10 x.acme.com # x client host
# localhost name resolution is handled within DNS itself.
127.0.0.1 localhost
# ::1 localhost
127.0.0.1 launcher.mlx.yt
Keep the following in mind:
- Make sure the line appears only once in the file
- Leave an empty line at the end of the file to avoid issues
macOS
Option 1: edit via one command in Terminal
- Open “Terminal” (search for it in “Spotlight” or find it in “Applications” → “Utilities”)
- Type the following command:
echo "127.0.0.1 launcher.mlx.yt" | sudo tee -a /etc/hosts - Press Enter
- Enter your admin password when asked
Option 2: edit manually via Nano text editor
- Open “Terminal” (search for it in “Spotlight” or find it in “Applications” → “Utilities”)
- Type the following command to open the editor Nano:
sudo nano /etc/hosts - macOS will request the administrator password – type your Mac user password and press Enter to confirm
- Add this line at the end of the file:
127.0.0.1 launcher.mlx.yt - Press Control + X to save the changes
- Press Y to confirm saving the changes
- Press Enter to finalize and exit Nano (the text editor)
Before you continue, clear your DNS cache. It can help the app connect more smoothly. Follow these steps:
- Open “Terminal” (search for it in “Spotlight” or find it in “Applications” → “Utilities”)
- Type the following command:
sudo dscacheutil -flushcache - Press Enter
- Enter your admin password when asked
- Type the other command:
sudo killall -HUP mDNSResponder - Press Enter
- Relaunch the app
The hosts file should look the similar way:
File reference
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting. Do not change this entry.
##
127.0.0.1 localhost
255.255.255.255 broadcasthost
::1 localhost
127.0.0.1 launcher.mlx.yt Keep the following in mind:
- Make sure the line appears only once in the file
- Leave an empty line at the end of the file to avoid issues
Linux
Keep in mind that the article is written for Ubuntu. The other distributions are not officially supported.
- Open “Terminal” (search for it in “Show Apps”)
- Type the following command to open the editor Nano:
sudo nano /etc/hosts - Linux will request the administrator password – type your Linux user password and press Enter to confirm
- Add this line at the list of IPv4 addresses (first several lines):
127.0.0.1 launcher.mlx.yt - Press CTRL + X to save the changes
- Press Y to confirm saving the changes
- Press Enter to finalize and exit Nano (the text editor)

Before you continue, clear your DNS cache. It can help the app connect more smoothly. Follow these steps:
- Open “Terminal” (search for it in “Show Apps”)
- Type the following command:
resolvectl flush-caches - Press Enter
- Relaunch the app
The hosts file should look like this:
File reference
127.0.0.1 localhost
127.0.1.1 <your PC and user name>
127.0.0.1 launcher.mlx.yt
# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allroutersKeep the following in mind:
- Make sure the line appears only once in the file
- Leave an empty line at the end of the file to avoid issues
Did the fix not work? Check this article: How to fix system timezone sync issues in Multilogin.