The HTTP(S) API syntax that you are using is the syntax for Blynk Legacy, and the cloud server url and IP addresses are those for Blynk Legacy, so the wont work with Blynk IoT.
The documentation for the Blynk IoT HTTP(s) API is here:
I’s suggest that you read it all, including the “Troubleshooting” section which contains information about the correct URL to use if you are using services like IFTTT.