Problem:
When running apt update, you see the following error message:
Err:14 https://repo.skype.com/deb stable InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 1F3045A5DF7587C3
Solution:
This error occurs due to the Skype repo using the outdated (as of April 2022) apt-key method of importing keys.
You can import the key using the following commands:
wget -qO- https://repo.skype.com/data/SKYPE-GPG-KEY | gpg --dearmor | sudo tee /usr/share/keyrings/skype-archive-keyring.gpg echo "deb [signed-by=/usr/share/keyrings/skype-archive-keyring.gpg] https://repo.skype.com/deb stable main" > /etc/apt/sources.list.d/skype-stable.list
and then running
apt update
again.