Facebook is investigating a fault on a mobile e-mail notification service it provides for BlackBerry users, technology website PC World reports.
According to the report, Facebook has received complaints from a group of users called 'Facebook for BlackBerry smartphones', who say they are not able to receive notification of a new Facebook messages to their e-mail accounts.
"We are aware that a small minority of our users are experiencing problems with e-mail notifications. We are actively investigating the issue at the moment and hope to resolve it soon," the company said in a statement.
The feature should send messages to the user's registered e-mail address, together with a link to the Facebook conversation thread .
Facebook has stated that users need to switch on the e-mail notification feature for it to work.
Even so, the users have complained that they still do not receive an alert e-mail after activating the feature.
Some users have also said that Facebook e-mail notifications are being sent to their junk folder, which the company has said can be prevented by marking the "facebookmail.com" domain as safe.