Happening on most worlds for me (I play 14). Which means that today I could not do the Rival (quest 2 includes donating goods to the guild) or a number of DCs, unless I shelled out a ton of sparklies.
One would THINK that the devs, who are apparently aware of the issue, would go in and edit the Rival quests and any DCs to ensure there is no requirement that can't be fulfilled until the system works again.
Wouldn't be so bad if it were a one-day glitch, but this has been going on for a bit now....
And restarting the game did precisely... nothing.