Having sent out a letter to nearly 1000 companies ~ introducing my new
company and asking for email confirmation that they belong to a certain
regulatory body ~ I've eagerly  been awaiting responses.

My stats counter would suggest that people are looking at my website and
yes, some companies are responding as requested.

Mind you two messages took over 20 hours to arrive in my inbox!

What concerns me however is that I had a phone call late yesterday from one
woman to say that she had tried a number of times to send an email and each
time it had failed.  Today another person contacted me to say they tried 3
times to send an email and on each occasion it bounced back.  So far as I can
see they were using the correct email address. I don't know what these error
messages said.

I have tried sending test messages to myself through AOL and hotmail.  These
work.  In addition I contacted the company providing the email account to
check if they could identify a problem ... and they assure me there is
nothing wrong with their server.

What worries me is that people may be trying to get in touch but are having
email returned.  As a new business this is the last thing I need.  The
trouble is I have no idea how big or small the problem is.

I use Trend Micro PC-cillin.  I am wondering if this could be part of the
problem and have turned off the mail scanning facility for both email client
POP3 (incoming and outgoing) and webmail.  Or... should I turn that back on?

Basically any ideas why some email gets through to me and why some does not?

Thank you.