Note: That is text, not an advertisement. I’ve never seen this before, have any of you?
I have in the past but it is pretty rare. Does it happen all the time or is it just at random times? If so it may be because the site is temporarily overloaded or some maintenance is being done.
That just means that the website that ad belongs to is down for whatever reason and because it can’t be accessed it gives you the 503 “Service Unavailable” error. It’s not an issue on ROBLOX’s end. Once the people maintaining that site realize there’s an issue, they’ll fix it and you’ll see their ads instead of the 503 error again.
I have OBC. I don’t see offsite ads.