Calling computer savy people...HELP!

[Will Crocker]

I've been posting ads on Craigslist 3x per day and have been getting some people emailing me back using the CL anonymous email they provide. When I try to reply to these people the email doesn't get sent. (It appears like it sent but the recipient never receives it.) It sits in my sent mail box but doesn't actually go through to the other side. I know this because I have tried emailing myself using different emails. Has anyone else run into this issue? How did you fix it?

There are posts online about it happening to other people but no actual answers to fix it.