W: Failed to fetch
http://debian.mirrors.ovh.net/debian/dists/jessie-updates/InReleaseUnable to find expected entry 'main/source/Sources' in Release file (Wrong sources.list entry or malformed file)
You should remove the jessie-updates from your /etc/apt/sources.list:
deb http://debian.mirrors.ovh.net/debian jessie main
deb-src http://debian.mirrors.ovh.net/debian jessie main
deb http://security.debian.org/ jessie/updates main
deb-src http://security.debian.org/ jessie/updates main
deb http://software.virtualmin.com/vm/6/gpl/apt virtualmin-jessie main
deb http://software.virtualmin.com/vm/6/gpl/apt virtualmin-universal main
see : Failed to fetch jessie backports repository and Debian apt-get update says ''Unable to find expected entry"
W: Failed to fetch
https://packages.sury.org/php/dists/jessie/InRelease
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: https://packages.sury.org jessie InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B188E2B695BD4743
Because the the siging key has been changed in 18 Mars 2019 by Ondřej Surý (A debian developper, php maintainer and more ...). You need to update the signing key.
packages.sury.org Debian repository GPG key has been changed
I was informed that the current DPA signing key
DF3D585DB8F0EB658690A554AC0E47584A7A714Dwas present on the server maintained by an other user of the repositories that got compromised. I do not believe that the users of the packages.sury.org repositories are at any risk because launching attack on the APT repositories using a compromised key would require also attacking other components in the path (HTTPS certificate and DNSSEC), but nevertheless, I have generated a new GPG key to sign the repositories with:15058500A0235D97F5D10063B188E2B695BD4743. To verify the authenticity of the new key, you can check that there's a signature from my personal signing key:30B9 33D8 0FCE 3D98 1A2D 38FB 0C99 B70E F4FC BB07.
To update the APT signing key, you can download the new key from the respective repositories, f.e. for the PHP, you would do:
wget -O /etc/apt/trusted.gpg.d/php.gpg https://packages.sury.org/php/apt.gpg
This doesn't affect any of the Launchpad PPAs, only the Debian packages hosted at packages.sury.org.