Group help please!

[OhHeyMarina 285]

I started a group called "December 2016 sleevers" some are able to join with no issue but majority it is telling them that they can't and that they need a password! I made the group open and available to anyone can someone tell me why it's doing that? This was my first group and I'm only on this site for about a week and a half so I'm still learning did I do something wrong that it's asking some people for a password and some can just join?

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[sleeveisa 333]

Where located?

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[OhHeyMarina 285]

to find it you just have to search December 2016 sleevers and then on the right hang side make sure you are under groups not forums and its the only group but some people can't join for some reason