web download certificate expiration

I am using SCUP to distribute Adobe Flash to my SCCM environment.

I have a distributer license.

The website which is hosting the Flash download location for SCUP is giving a certificate error.

"The security certificate presented by this website was not issued by a trusted certificate authority."

SCUP error log

Download file: https://fpdownload.macromedia.com/.../install_flash_player_21_active_x.msi failed with message "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel."