Group email account sometimes shows, Then disappears

Hi all

I’m admin of a car club who is trying to set up a CRM back end to manage day to day tasks for the club. The club is run like a business so a CRM works well so far.
I have just started to look at creating group e-mail accounts so staff with the correct permissions can view the mail on the merchandise account for example or the IT staff can see the mail in the support mail account.

So far i have added the merchandise email to the system and have managed to get it working. However there seems to be a couple of problems.
The first one being the e-mail account sometimes shows in the folder list and works fine,but other times it’s missing. See pictures.

How can i get it to appear all the time? Is this a bug?

The second question is how do i add another group e-mail account and set permissions for different users to access it? There seems to be no user security for email accounts.

Thanks
Mathew

Can anyone help with this please?