My Team not able to access all contacts

My Team not able to access all contacts

Hi,

My team has been given access to view all contacts available in Zoho CRM, but they are not able to view them. They are getting the message that (the record you are trying to access is not available), yesterday only we gave access to view all contacts and after giving the contacts were visible but again today morning the access got changed without us changing anything. And this happened twice. 

Please look into what is the issue.