Search for a game in a specific plarform

Hi, everyone

I want to search for a game on a specific platform, i tried:

https://www.giantbomb.com/api/search/?api_key=`my api key'&query=%27call%20of%20duty%27&resources=game&filter=platforms:145

It should search for "call of duty" on Xbox platform, but id does not, it retrieve results from multiple platforms

any help?

thanks in advance