top reason:

when you get a topic notification reply, a personal message notification etc. and i get a

CODE
<XXXXXXXXXXX@yahoo.com>:
failed after I sent the message.
Remote host said: 554 delivery error: dd Sorry your message to XXXXXXXXXXXX@yahoo.com cannot be delivered. This
account has been disabled or discontinued [#102]. - mta199.mail.mud.yahoo.com


i will ban those accounts immediately.

it is your responsibility to keep your email current. No email - No access.

-
if thats your case and you have not broken any rules, do contact me ASAP

with:
- your forum username
- the email that was used for the account.

unless i deleted the account i will be able to change the email to a valid one and reenable your account.