Debian wheezy is no longer supported. It is two major releases older than stable. It has not received any updates since 31 May 2018. The resolution is to dist-upgrade to oldstable, or to stable.
You can still use the archive repository but there is no more updates:
deb http://archive.debian.org/debian wheezy main deb http://archive.debian.org/debian-archive/debian-security/ wheezy updates/main