Every time I open the appcenter there is a message of "Failed to fetch updates" Everything seems to be working fine, but I would like to solve it
Here is the full content of the window
W: Ignoring file 'brave-hera.list.' in directory '/etc/apt/sources.list.d/' as it has an invalid filename extension E: Release file for http://packages.elementary.io/appcenter/dists/bionic/InRelease is not valid yet (invalid for another 7h 57min 2s). Updates for this repository will not be applied. E: Release file for http://security.ubuntu.com/ubuntu/dists/bionic-security/InRelease is not valid yet (invalid for another 1h 9min 2s). Updates for this repository will not be applied. E: Release file for http://it.archive.ubuntu.com/ubuntu/dists/bionic-updates/InRelease is not valid yet (invalid for another 3h 17min 26s). Updates for this repository will not be applied. E: Release file for http://it.archive.ubuntu.com/ubuntu/dists/bionic-backports/InRelease is not valid yet (invalid for another 1h 11min 15s). Updates for this repository will not be applied. E: The repository 'http://ppa.launchpad.net/nvbn-rm/ppa/ubuntu bionic Release' does not have a Release file. W: Updating from such a repository can't be done securely, and is therefore disabled by default. W: See apt-secure(8) manpage for repository creation and user configuration details. E: Release file for http://ppa.launchpad.net/elementary-os/stable/ubuntu/dists/bionic/InRelease is not valid yet (invalid for another 7h 26min 49s). Updates for this repository will not be applied
Thank you very much for your help in advance.