Hi! This is very likely due to the fact that your friends don't have the game mode unlocked that you're trying to play. If you've purchased the base game they can use one of their scrolls to unlock that for 24 hours as well.
Hi! It seems like you're not logging into the same account. Kindly contact our technical support at firstname.lastname@example.org. Just share with them your account name that shows up when you play on steam. They will be able to help you out!