Players unable to find/join guild without an invite

[npr04]

Hi, we have started a new guild a couple of weeks ago and there are now 25 of us. Initially there were 22 that started up the guild. All have needed an invite and although it is set to open to join. It seems only people we physically invite can join. They have even told us when using advanced search the guild cannot be found. Any know how I sort this out?