Ministering Assignments - Missing Youth

I am trying to assign youth (priests and teachers) as ministering companions with some elders and I am missing the name(s) of said youth from the drop-down menu of options to add a companion. I've tried checking both the assigned and unassigned lists and he doesn't appear. I checked the ward directory on LDS.org and their name(s) appear there though. Very curious. Is there something I can do to rectify this situation?

Have you tried typing the name?

Yes, the name doesn't appear. Very strange.

If you can assign some and not others, you might inspect one or two from each group and look for differences in their membership record.

You might want to verify that they are not a out-of-unit member. (A child that's split between two wards.) I didn't think they showed on the directory, but I could be wrong.

Also verify they're not a deacon.