I had a Repository error on Linux and this is how I solved it with the help of others who have asked how to fix this from the Reddit community.
I had a Spotify error where the Pubkey was no-longer valid for apt - This is how I solved it in the Linux terminal.
"The following signatures couldn't be verified because the public key is not available: NO_PUBKEY D1742AD60D811D58"
The solution I followed was found here: / errors_while_running_updates
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TechManPat
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