Port 443 is used for Secure Sockets Layer (SSL) or essentially, the "s" in HTTPS; the secure protocol for web surfing. If this port is closed on your firewall, then you (nor any application that typically uses it) cannot access any secured web site (store sites, logins, etc...).
This port is typically open by default, so if it's closed now, there's likely something else wrong with your system and I'd be running security scans (anti-mailware/spyware and anti-virus).
If your scans come back clean, access your firewall and make sure the port is open and available.
-Wolf sends