That seems like a PPA error. Do you have any restrictions for the SSL certificates?
I am using the byteit101 repo without a glitch. Have you run apt-get update yet?
That’s bizarre. Are you up-to-date on all your other packages? There’s nothing fancy about my PPA, and that error seems to be about missing certificates, which might have been recently issued if you haven’t installed updates in a long time. update and upgrade, then see if it still fails.
What happens when you access https://launchpad.net/ directly through a web browser? Can you double check and make sure the system time is correct on your Linux machine?