Same issue. I updated Java yesterday before I played FTB Revelation, and it loaded up fine after that. I did not restart my computer until this morning after having this issue. The pack did not update. Restarting did not help. I tried changing the date to yesterday because some modders base things on the date, which did nothing. I tried forcing update, deleting the modpack, deleting the modpack and 1.12.2 version foider, no change.
Like someone else above, I tried removing GenDustry and it got further but still died. I didn't catch what it crashed on.
I think I caught somewhere that the game might be requesting some live stuff that might be down right now? idk.
i checked my update log, and it looked like windows had an update to me last night. And i could play yesterday, and not today
I update windows before yesterday and it was working fine. There were no updates between then and when this started.