Can't transfer calls - just beeps?

We’ve recently had a snag with one of our Asterisk boxes. When we get a call come in from outside via ISDN to our call centre it can’t be transffered beyond that to anyone else in the company.

We simply get the ‘beep’ sound down the phone. As if the “*” key no longer puts people on hold.

Does anyone have any ideas?

By clicking the ‘#’ key you can get an instant transfer. Though pressing ‘’ simply does nothing. Its as if the '’ key has lost its ability to place calls on hold.

Any ideas?

I’ve checked features.conf and it states:

atxfer => *

So this should work - alas it is not.