make sure that nothing changed with your mail server. you may have to ask your host about it. you haven't made any modifications to your forum that would effect inc_mail.asp or did you change anything in the email set up?
have you installed any mods? did you make changes to the email config in admin options? have you asked your host if they've changed anything about your email server? has mail ever worked before?
answer those questions first. (chances are if you don't know what inc_mail is then you haven't modified it.)
I dont know if email has worked before, i just recently set up the subscrips and as far as i know it probably hasnt ever worked. I never touched either of the two things. I didnt email my host and waiting to hear from them. I too feel it is something on there end.
as far as everything. email component, email server address (is it right?) and anything else listed there. it may be that you have something set incorrectly.
As far as I know it is set correctly. I didnt set it up my host did, but I have emailed them to find out all is correct. I know they added a firewall after they set me up with the forum. I am sure it has to do with that.