On the Rockstar Games support site there was a message about maintenance work in the PC version GTA Online.
For some players, GTA Online on PC may not be available on Wednesday, June 22nd between 8:00 a.m. and 1:00 p.m. ET. The servers will start working again as soon as the technical work is over.
Such interruptions in the work of “Online” happen quite rarely. Perhaps tomorrow is connected with imminent update of the game to the nextgen version. As for the new DLC, then, according to Tez2we need to wait until the end of July.
Source: gta.com.ua