In that case, you need to configure the same proxy to enable Bitdefender Update.
In one of our previous article, we had covered in-detail about Configuring Proxy for Bitdefender Antivirus Update needs. Please do this only if you are using other proxy server for browsing.
First of all, enable Automatic Update, which is a lot more essential for your security.
Powerful scan engines ensure detection and removal of all malware, from viruses, worms and Trojans, to ransomware, zero-day exploits, rootkits and spyware.
Bitdefender Antivirus Free Edition is an antivirus to rely on.
Are you using another Firewall software for your computer?
If so, this might be interfering the connection between your PC and Bitdefender Update servers.
Bitdefender Antivirus Free Edition uses behavioral detection to closely monitor your active apps.