Like gizmo,
I have been down that road of being blacklisted using the built in mailer twice.
First thing blacklisted does is block all emails from your boards primary email.
Meaning forgot password,PM/topic notifications etc..
And it takes forever to get the main email address restored.
Just like spiders your have multiple blacklists.
And you need to wade through each one.
The hard part is finding each one.
Some use services ,some domains make there own.
Which entails phone calls to each it department involved...
Having bounced emails is normal on a old board, especially where the member has not visited in a long time and has changed their email but not updated their account.
You are better off downloading a mail list from ubb and importing it to a mail list server using a different email address that what the board uses.
If that gets blacklisted at least the forum still functions on notifications
