I have a function in a workflow that trigger when lead is created, the function is working fine for more than 2 years but recently we're having this issue were it fails and the reason for failure is HTTP Status 400 – Bad Request.

However when I execute the function manually on same exact leads that it fails at first time, then the function works, so I don't understand what is the issue why it's working when I execute manually and when workflow trigger's it doesn't?