Bouncing members
A bouncing member is a member who is not receiving email messages from your group. The email account may have been closed or deleted or the mailbox may be full. Either way, they cannot participate properly in your group.
To see which of your members are bouncing, you can click on Members>Approved then select Bouncing from the drop down options. Against each of those members you have the option to click to Reactivate button in the pink bouncing announcement panel.
Members can also see, when they log into the site, that they are bouncing and can also choose to reactive by clicking the button.
It is a good idea to check this list on a regular basis and try to reactive your bouncing members. If you have reactivated them several times over a period of months and they have posted no posts or seem active for a long time, you can remove them. They can easily join again if they wish!