I have a problem and it is that in the lobby it does not let my friends see, they appear invisible and it does not let the robbery start, even in the chat it says that the connection has been lost, how do I solve it?

If you/your friends run mods - try to check the issue without them

If not
http://steamcommunity.com/app/218620/discussions/14/412446292758934434/?ctp=2#c358415206095910647
https://support.steampowered.com/kb_article.php?ref=9828-SFLZ-9289
if you dont run these programs - add payday 2 as exception for your antivirus and firewall and try to start the game without non-essential programs as administrator
http://steamcommunity.com/app/218620/discussions/14/412446292758934434/#c412447331647614749
https://support.steampowered.com/kb_article.php?ref=3134-TIAL-4638
And try to change steam download region to next closest one to you (your friends should do the same)

it didn't work

Hi. Can you try some basic stuff when this happens?
- Both a client and a host try restarting Steam program
- Change or make a new loadout profile in-game.
- Swap a host to see if it helps or not.

nop , it didn't work