Description of error codes in API responses

If an error occurs when requesting the API, the system will issue a message like:

{"error_code":1}

Where the parameter error_code can take one of the following values:

1
General error: contact support for clarification
2
Digital signature verification error
3
The method is not available
4
Partner identification error
5
Project definition error
6
The payment method is not available for this project
7
This payment method is not available for the project
8
Invalid parameter user_data
9
Insufficient funds on the balance sheet to make the payment
10
Transaction not found
11
Payment is not available for this source