[otrs] Forgot password mechanism doesn't send email.

Hi All, Having a strange issue, quite a new install of OTRS have never had chance to see if this was working earlier and broke or just never worked but it seems that when a user uses the forgot password link on the cutomer portal login page they never receive an email. I checked this and indeed there is no email sent by OTRS I cannot see one being queued in the postfix log and nothing logged in OTRS's log, All other mail out of OTRS is working perfectly. I was running OTRS helpdesk 3.2.8 on CentOS 6.4_x86 but just upgraded to 3.2.10 to see if this would fix but still get the same issue. Any ideas? Thanks, Steve.