[Spryng] Why does API respond «invalid_fields: processors»?

I am making a payment transaction in the test mode:
https://sandbox.spryngpayments.com/v1/transaction

The API responds:

{
   "code": 110,
   "details": {
      "resource": "account",
      "invalid_fields": [
         "processors"
      ]
   },
   "message": "invalid requested resource"
}

I checked the Processors settings in my account. It has the dummy_processor1 value:

I also found the following information in the documentation about processors:
https://api.spryngpayments.com/v1/#section/Embedded-Object-Types/Processor-Configurations
It says:

Because we interact with different payment processors to process different type of transactions, different configuration are also needed: one for each processor available for a given account.

But I do not see such configuration in my account.

I have got a response from the Spryng support:

On your account you had ‘dummy_processor’, I changed this to ‘card_dummy’. The same call should now work.