This type of connection cannot be checked for viruses

Hello! While at work, I experienced some slow down of my computer and I decided to scan for some viruses that might infect my computer.
While avast was scanning it generated an error message, the error is so technical.
Please see below the error message screen.

Avast Information
Avast! Has detected a secure connection from your mail
program (process wlmail.exe) to the SMTP server
This type of connection cannot be checked for viruses.
Please disable SSL/TLS I your mail client so that the
Mail Scanner can scan your mail. The Mail Scanner will
provide the SSL/TLS security itself.
When I looked upon the error, it was too complicated for me to understand, since I am not a technical person to understand the error message. I searched the internet for some solutions, but I found nothing that fits with my problem. I am posting this issue here, hoping to get some solution to my problem in scanning my computer for some virus using Avast.
Thank you.
