So I've been trying to update to Ubuntu 21.10 but after it prepares to update I get this message:
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.,
W:GPG error: https://dl.winehq.org/wine-builds/ubuntu impish InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 76F1A20FF987672F,
E:The repository 'https://dl.winehq.org/wine-builds/ubuntu impish InRelease' is not signed.,
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.,
W:Target Sources (restricted/source/Sources) is configured multiple times in /etc/apt/sources.list:2 and /etc/apt/sources.list:7
I've tried other solutions from similar issues, but nothing seems to work. I'm not an expert with Linux so can you guys give me some ideas on how to fix this?