Similarly, you may ask, why can't I play Borderlands 3 online?
First, you need a premium Xbox Live account to play online. If you haven't paid for Xbox Live Gold membership, then this might be the reason why Borderlands 3 multiplayer is not working. Second, your Xbox Live account or gamertag may not be configured properly in order to allow you play online.
Beside above, why can't I join my friend in Borderlands 3? If your friend is in a full four-player session, you will be unable to join them and their group will be unable to join you. If they are not in a full session but you still cannot invite/join them, their Group Privacy Mode may be set to Local Only.
Furthermore, do you need online to play Borderlands 3?
An internet connection is required to access Borderlands 3's online functionality and co-op matchmaking, but much as with previous Borderlands games you can play entirely solo if you want.
Can I play Borderlands 3 on Steam if I bought it on Epic?
According to Tim, Borderlands 3 PC players will be able to play the game together, regardless of purchase store. The game will come to Steam after its 6-month exclusivity period on Epic Store. Keeping that in mind, Borderlands 3 Epic Games Store and Steam cross-play will not be available until the first half of 2020.