That is what Avast is complaining about.
avast isn't complaining. It is doing what it is supposed to do. Protecting the users systems.
Асхаб
several problems can be avoided by using a dedicated server instead of a shared one.
If there is a malicious website on a shared server and the IP gets blacklisted/blocked, it will mean that your website also will be blocked, even when it is clean.
As said before, cleanup your site to solve at least one of the problems.