Cannot join game

[shadow mural]

I have a question, which is mainly why I joined...

I wanted to join my friend in coop, which we have been doing for the last week. However for some reason I keep getting "The game you have tried to join is no longer available" even while he is currently playing.
I have been playing Hellraid and I have set the game to save back in campaign mode, as he does not have this DLC.
but even still I keep getting this error all the time.
It joins, it gives me the load save option to join with, and then after it joined, it kicks me back out and says this message.
What can I do?
We're playing on steam and PC

So the screens I see when trying to join are the following screens:

"You are trying to join a VAC secured game. Do you want to turn on VAC in order to join the game?"

• Hit "Enter" or Yes

"The game session you are about to join is taking place in the same area. Select 'Yes' to join or 'No' to return to the main menu where you may select another save or discard the invite."

• Hit "Enter" or yes

"Note that only direct continuation of your current quests will be saved in this co-op session. Character development and inventory will be saves normally. Are you sure you want to join other player's game session?"

• Hit "Enter" or yes

Then I get a save screen black, with the saving icon in the bottom. Then a black screen for a while, and then I get the message "Unable to join the game. The game you have tried to join is no longer available."

like wtf...??

When I do it from the main menu instead I get the following screens:

"You are trying to join a VAC secured game...."

• Hit "enter" or "yes"

Some "load save" like screen where I can select a save with which I want to join.
I have to note that I only have one save at this point, which is the very save I have been playing this game with the guy with for the last couple of days

[robust reef]

This is for dying light 2 not dying light 1

[shadow mural]

Sozz

So where is the DL1 support?