After attempting to update within the command line, the system ends with these errors.
Reading package lists... Done W: GPG error: https://repo.skype.com/deb stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1F3045A5DF7587C3 E: The repository 'https://repo.skype.com/deb stable InRelease' is not signed. N: Updating from such a repository can't be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.