Activate AVG email singature option

Hello Antonio,
We kindly request you to follow the instructions on the article http://support.avg.com/SupportArticleView?urlname=How-to-troubleshoot-your-email-scanning-protection and check whether the AVG program initializes the scan.
Please feel free to contact us for further assistance.
Thank you.

Hi,
I use Thunderbird to my gmail account
When I activate AVG email signature option, my sent emails have 3 bottom lines but inform the email was verified with Avast

"—
Este e-mail foi verificado em termos de vírus pelo software antivírus Avast.
https://www.avast.com/antivirus  "

I never installed Avast in my PC and I already checked installed programs.

If I remove the flag "activate AVG email signature" in AVG options, my, sent emails doesn't have any mention to Avast.

How can I solve this matter?

Thanks for your reply.

My ports are correct added to AVG - this is not the problem.
The problem is if I checked AVG email signature my emails are sent with "verified with Avast" not with AVG and I never installed Avast in my PC

AVG email's signature is doing know by Avast?

Thanks for your reply.
I was afraid that was a virus disabling AVG signature.
I didn't know AVG belongs to AVAST

Best regards