I've created the process with similar signal. It works fine and the process is launched:
Most likely your created call doesn't satisfy your signal conditions. Try to disable the filter and see if the process launches or make sure the call record satisfies it.
The settings seem to be fine and the process should have launched the process. What I suggest is to try is to disable the background execution in the signal settings. If this cannot help - try to re-add the signal completely. If still no success - it is necessary to investigate the trigger on the database level. In this case it is better to approach the support team. I'm afraid it might necessary to have a closer look to the website, rather than trying to guess the possible solution.