set default devicemanager endpoint as /dm/execute. As stated in VCHASNO docs.

api/client.go

@@ -40,6 +40,6 @@ func NewDMClient(token, dmURL, device string) *Client {
 		device:         device,
 		resty:          restyClient,
 		apiBaseURL:     dmURL,
-		fiscalEndpoint: "/dm/fiscal",
+		fiscalEndpoint: "/dm/execute",
 	}
 }

api/fiscal.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
+	"log"
 )
 
 func (c *Client) executeRequest(ctx context.Context, request FiscalRequest, response interface{}) error {
@@ -15,31 +16,34 @@ func (c *Client) executeRequest(ctx context.Context, request FiscalRequest, resp
 		return fmt.Errorf("failed to marshal request: %w", err)
 	}
 
+	url := c.apiBaseURL + c.fiscalEndpoint
+	log.Printf("[VCHASNO] POST %s", url)
+	log.Printf("[VCHASNO] Request: %s", string(reqJson))
+
 	resp, err := c.resty.R().
 		SetContext(ctx).
 		SetHeader("Authorization", c.token).
+		SetHeader("Content-Type", "application/json").
 		SetBody(reqJson).
-		Post(c.apiBaseURL + c.fiscalEndpoint)
+		Post(url)
 
 	if err != nil {
 		return fmt.Errorf("request failed: %w", err)
 	}
 
-	if resp.IsError() {
-		return fmt.Errorf("api error: %v", resp.Error())
-	}
-
-	if resp.StatusCode() != 200 {
-		return fmt.Errorf("unexpected status code: %d", resp.StatusCode())
-	}
-
 	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return fmt.Errorf("failed to read response: %w", err)
 	}
 
+	log.Printf("[VCHASNO] Response (status %d): %s", resp.StatusCode(), string(body))
+
+	if resp.StatusCode() != 200 {
+		return fmt.Errorf("api error (status %d): %s", resp.StatusCode(), string(body))
+	}
+
 	if err := json.Unmarshal(body, response); err != nil {
-		return fmt.Errorf("failed to unmarshal response: %w", err)
+		return fmt.Errorf("failed to unmarshal response: %w, body: %s", err, string(body))
 	}
 
 	return nil