Email retention

Hello, some email messages that I was sending from one of my accounts to another in the same domain were not being received. I contacted the company responsible for hosting the website and emails and they said that many users have this problem when using Avast. I interrupted Avast for 10 minutes and immediately received the missing emails. The company strongly recommends all of their clients not to use Avast due to this problem. Is there anything I should do before migrating to another antivirus software that could solve this issue?

Thanks in advance for any help.

What is your email client and what is your domain name?

If this is used in a business environment see http://forum.avast.com/index.php?board=33.0