As I stated the problem in the tile,We have an account it has two task lists that are shared with several other accounts.Most of the accounts have a Manager level permission on these shared task list.Meaning,these accounts should be able to add,delete and modify items.However,the problem is that when accounts with the manager level permission attempt to add items to the list,they first appear but later disappear.I'm not sure how to start troubleshooting as I am not very familiar with Zimbra.Any input would be highly appreciated.

Thanks in advance,