Can't give control of a token to one of my players

I think that the title says it all. I am curently making tokens for my players, but when I want to give access to one of them to one of my players, his name doesn't show. When I edit the token and select the ''Controled By'' tab, I see the name of all my players except for his name. It's pretty odd since I actually see his name in the list of my campaign players before lauching the game. Thank you in advance for any replies.

If he hasn't actually launched the campaign and used the app, I don't believe you can give them access to a token or assign them control of any journal entries.

HoneyBadger is correct, your players must actually enter the game before they can be assigned any resources. - Gauss

Thank you!