Mac Mail and AOL IMAP

Post the error message (Connection Doctor>Details) that goes with the little red ball.

Please verify that you are adhering to these settings.

AOL Imap (incoming)

• AOL Mail IMAP server address: imap.aol.com
• AOL Mail IMAP user name: Your AOL Mail screen name (the part before "@aol.com" in your AOL Mail address; if your AOL Mail address is me@aol.com, for instance, the screen name is "me")
• AOL Mail IMAP password: Your AOL Mail password
• AOL Mail IMAP port: 993
• AOL Mail IMAP TLS/SSL required: yes

AOL Smtp (outgoing)

• AOL Mail SMTP server address: smtp.aol.com
• AOL Mail SMTP user name: Your AOL Mail screen name (what comes before "@aol.com" in your AOL Mail address; if your address is me@aol.com, for example, the corresponding screen name is "me")
• AOL Mail SMTP password: Your AOL Mail password
• AOL Mail SMTP port: 587
• AOL Mail SMTP TLS/SSL required: yes

Remove the account, reboot, enter the account (in Mail, Contacts and Calendars, located in System Preferences).

1 you are not entering the settings correctly

2 AOL is borked

3 You don't actually have a connection to AOL at this time

Assuming 1 is not the case and 2 is not the case (neither of which are proven) let's test 3

Open terminal, at the prompt type this. Ping imap.aol.com, repeat with smtp.aol.com

Post back

Get rid of Avast, it does not protect you at all and will screw up many other thngs (as you have found)