I was successfully using the post by email feature but when it was removed in 3.7 it broke a key feature of our fire department web site.
I installed the Post By Email plugin (ver. 1.0.4b) and it copied the configuration settings I had before that worked.
However, I'm getting "An error occurred: Error connecting to POP3 server." when I run Check Now.
I installed Postie and I am able to connect and I can connect using the Gmail web site using the same username and password. I also tried reentering the login info but it still didn't work.
I am on Hostgator, with version 5.2.17 of PHP
Setting for Gmail
always use secure connection is checked