Matrix field in user-profile front-end
It works identically to entries. 

Here are a couple things you can do to troubleshoot:


Make sure that user is set to the user account you’re expecting it is. You can double check that by outputting {{ user.username }}.
Make sure that you’re calling the right Matrix field handle, with the correct capitalization.
If you’re passing the type param, make sure you’re passing in the right Block Type handle.