As of firmware version 7.14, direct HTTP GET requests have been removed from the Teltonika devices. These functions are now handled through a more secure API interface.
Although this page refers to the RUT955, the same commands should also work for the RUT956.
Please note that using the API offers a more reliable and secure way to manage I/O operations, but it is only available after updating to a newer firmware version. We therefore recommend updating your device to the latest firmware to take advantage of this functionality.