Cancelling an order on the exchange

I’m continously getting the following error when I try to cancel any active, unmet order I have on the exchange:

failoverAPI: Call failed (failed over across all servers). Method: broadcast_tx; Last error: JSON-RPC Error:

Type: Server error

Code: -32000

Message: Bad status code returned: '500'. result body: '{"result":null,"error":{"code":-26,"message":"64: scriptpubkey"},"id":0} '.

This has happened for at least a couple of days, even on different browsers (Firefox/Chromium), and even in incognito/private mode (which I suppose is free of any cookies or similar from earlier that might confuse Counterwallet). Of course, I could just wait a few more days until the order expires, but I wonder what is wrong. I’m on Ubuntu, in case that changes anything.

Yes, there is an issue with canceling open orders, it was reported here:

Oh, thanks!