I got the "...has not invited you to a dance" error.
I believe part of the problem may be using tabs to have multiple pages open, but I don't know if it's specifically having another ballroom tab open, or any Subeta tabs.
Even if the whole world rejected you, I'd still be here, by your side.
Same, also just got the "Oh No! [NPC] Gossip Boudewijn hasn't asked you to dance!" when clicking on the "no!" red button. (when yes, yes he really did ask me to dance he's just being mean.)
I also get blank pages. I'm able to view the source code of the duel page and click links that way but... talk about tedious. Especially if someone doesn't know how to skim through coding and look for the right thing.
Chiming in to say I'm still waiting on this to get fixed. I haven't accepted dances because I am one of the unlucky that this has glitched on.

I just got my first challenge, and I got the "hasn't asked you to dance" error. Awesome :L
Guess I'll sit here staring at 74 events while I wait on a fix smh
Blank page… Safari.
Thanks for mentioning that, I'm now doing that too since my duel pages are blank.

Do either of you have a page/address for this? All I can see is the address which is clearly wrong…
Well, I don't think I can get in trouble for it as it is just a link and it doesn't necessarily take you straight to being able to battle him because it gives the "Oh No! [NPC] Gossip Boudewijn hasn't asked you to dance!" with the 404 error monster if you haven't encountered him and challenged him.
Since a lot of us are glitched here is the link for a choice: http://subeta.net/explore/masquerade.php?act=duel&choice=1
Just change the 1 at the end to a 2 or a 3 to pick something different. When it goes through the page will still be blank, but after you refresh the page a few times you'll either win or lose/draw.
Since this hasn't been fixed this is the only work-around. Please, if this is against the rules in any way let me know and I will edit this asap, but again I don't feel it is.

THANK YOU! :)
Okay -- so the link it provides when you click on the box is just an incomplete address then. I've hit the blank pages like 3 times now and it is SO frustrating! Especially since it only affects some users. I'll try this next time it happens.
You're welcome!
I should mention though that the only way to know if you've won is by finding a in your inventory(I think this is the only one he gives out, but don't quote me on that) or getting the respective achievements. Other than that for those of us that are glitched there's no way to tell.

[edit]NVM. I just chose the wrong choice in the popup.
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Happened to me twice last night and once this morning. :x I have no idea what I'm doing wrong here.
Yeah, I've just missed my duel too. I use safari and a mac if that helps.
Your suggestion regarding looking through the source code worked for me. I'll have to use this until they get around to fixing this.
My pages were still blank the entire time so I picked the different links until I reached the "NPC has not asked you to dance!" page