Can not cancel order.Error code 32000.Help me

I bought an order for Trigger token on January 1 at xcp dex exchanges. I can not cancel the order and the error message below will appear. Please tell me how to resolve.

falloverAPI: Call failed (across all servers). Method: get_optimal_fee_per_kb; Last error: JSON-RPC Error:

Type: Server error

Code: -32000

Message: Got back error from server: {‘code’: -32602, ‘message’: ‘Invalid params’, ‘data’: {‘args’: [“fee_per_kb() got an unexpected keyword argument ‘nblocks’”], ‘type’: ‘TypeError’, ‘message’: “fee_per_kb() got an unexpected keyword argument ‘nblocks’”}}