cannot search in outlook 2016 "all mailboxes"

Hey all,

I use outlook 2016, and i have 2 mailboxes (my mailbox and another full access mailbox)

When i select "all mailboxes" in my search tab, i cannot find anything, and if i select "current folder" i find mails, but only in the specific folder then is chose.

I tried to rebuild the outlook profile but it doesn't help.

Please help.