I tried this with my Yahoo Mail, and I could receive emails, but not send them. I tried sending one to my main AOL email from Planetweb and it said it send successfully, but I did not receive it on my main AOL email. I also sent an email from Sega Swirl, but I didn't get that one either. Looking in the cmailserver log, I can see that the email failed to send. It seems AOL blocks emails from residential IP addresses. So I setup the cmailserver account in Outlook Express on the computer running cmailserver for testing purposes. I tried to send an email to my same Yahoo email from Outlook Express, but that didn't work either. In cmailserver I got a scary error that said "FAILED: 421 4.7.0 [TSS09] All messages from <my public ip> temporarily deferred due to user complaints - 22.214.171.124; see https://help.yahoo.com/kb/postmaster/SLN3326.html
: yahoo.com(mx)" I don't know who would be complaining, I only tried to send a few emails to my personal AOL email address. So it seems this won't work to send email from Yahoo, or to send emails to AOL email address.