Sounds like your Avast is the problem. Usually certification refers to sites though, not people. You may want to try uninstalling the program, restart the computer, then see if your internet works. Which it will if it was Avast blocking you. In that case you will need to decide if you want to reinstall Avast and still use it, or try a different antivirus program.
If you choose to reinstall it, then I would contact the company that makes it and find out from them directly how to keep that from happening. No program should keep you from completely accessing the net. Specific sites sure, but not all sites.