Since Avast is not currently able to scan SSL, they have instituted changes in setting up your email.
Please click here for an article containing full instructions on Avast's website.
In order to change settings in IncrediMail, you will need to open the 'Mail Accounts Dialogue'.
To find your Email Settings, please click 'Tools', then 'Email Accounts', choose your account and click 'Properties'.
If you need further assistance with this article, please click here to contact Avast's Customer Service.