Chances morning will bring unwanted correspondence (4)
I believe the answer is:
spam
'unwanted correspondence' is the definition.
(I've seen this before)
'chances morning' is the wordplay.
'chances' becomes 'sp' (abbreviation for starting price in gambling).
'morning' becomes 'am'.
'sp'+'am'='SPAM'
'will bring' is the link.
(Other definitions for spam that I've seen before include "Possible item from menu" , "Unwanted e-mails" , "Food" , "Uninvited email" , "Junk email" .)