Gleam no longer supports Steam community giveaways. Steam Community has started blocking Gleam.io. Here is the official announcement.

Because of this problem the upcoming Big Fucking Giveaway 2 is going to be hosted on our site just as we did before (you just need to login and fill out the quiz!), it will probably keep on dying from all the traffic but it’s going to last for a whole week starting Big Fucking Giveaway 2 – August 22nd 2016 13:00 (1PM) so you will have plenty of time to participate.

Major groups currently affected with their accounts closed: REX, OGG, FreeGamesInfo, SuperGiveaways. I personally hate those groups and the way that they want to sell their “services”. Here is an example from SteamUnpowered’s Twitter and someone from REX (direct message from July 2016):