It looks like something went wrong on Blizzard's side with the recent patch, your guild doesn't seam to exist
on API, but does exist on Armory
. For example, API should return something like this
. Unfortunately, there's nothing we can do until Blizzard provides us with the data about your guild, since scraping data from Armory is not allowed. I'm sure this will be fixed in the next few days, I'll report it asap.