Program blocked

Hi,

I have developped a service program on windows.
This services is installed on customers computers. The program read data from database and send it by webservices on my server (every 15 minutes).

At each update, Avast systematically block the program…

Actually, i use a certificate wich is not certified. Is this explains that avast block the program ? Or, that it may come from other ?

I don’t want to use exception because, i have lot of customer…

Thanks,

What exact version of avast are you using?
What part of avast is blocking it?
Any message?