It works fine for me too. Try restarting the wifi/data of your cellphone and restarting the app after.
I guess 2 times it simple couldn't connect multiplayer, done the restarting ritual and worked.
Edit: yesterday I played a couple hours of multiplayer and the host got disconnected about 3 times. It was weird, but not completely unable to multiplayer for some hours though, we could join right after disconnected.
Pixel Fans... I dont think he got banned if he was banned he should have been complaining about why he got banned or he should have said he also gets a message about his account being banned and cowbeans is pretty much aware of people restarting or not saving then play again to get a better item from the daily bonus, if i remember correctly he said the game has an anti cheat method that makes people always fail in getting good items from daily bonuses when the game wasnt available for everyone only for those who are in his google group made for chosen alpha testers.
I didn't find a subreddit or another place to discuss psg3 besides the wikia, and kinda upsets me since there's so much in the game to be discussed.
About daily rewards I guess I've been naive and never tried anyways to retry the rolls, and truly and don't care that much. I've opened every breakable weapon from master/gold chests, so I accepted the fact that I need to buy from the Weaponsmith with is expensive as fuck. My point is that I'm not completely salty about it lol, just got unlucky.
The google group still exists but its forum page is closed in other words the group IS NOW CLOSED, im pretty sure it doesnt accept anymore join request. Since it was made for testing the game (making sure its much more stable so he doesnt get too much emails about bugs) before its actually released to many people labeled as an UNRELEASED game