Hi @vlado_vaco - the mapped method needs to be lowercase, e.g. get instead of GET.
In the Method field you can wrap your variable with the lower() formula like this:
lower( {{44.method}} )
… to dynamically transform it to lowercase.
If that still doesn’t work, make sure your method variable is correctly mapped/selected from the Get Variables module (not just typed in as plain text) and that it actually receives values/is not blank at runtime.