W: GPG error: http://archive.ubuntu.com trusty Release: The following signatures were invalid: BADSIG 16126D3A3E5C1192 Ubuntu Extras Archive Automatic Signing Key <ftpmaster@ubuntu.com>
I tried the accepted solution offered in this link but it did not solve my problem.
I did not try the solution provided Portablejim because I did not understand what the key 16126D3A3E5C1192 is for in the command:
sudo apt-key del 16126D3A3E5C1192
I also changed servers to download from but no luck.