Security is a moving target at Fermilab, so we've introduced a script you can use which should do all the authentication steps required to interact with the computing resources.
Interactively, using the command will setup everything you need, including a kerberos ticket if you need one. It may ask you for your kerberos password.
Inside another program (such as cafe or another script) you can run the following command which will setup the certificates and proxies but not ask for a password.
If you are having problems, you can force everything to be regenerated with:
$ setup_fnal_security -h Setup the tickets, certificates, and proxies required to use FNAL computing usage: setup_fnal_security [options] options: -h/--help: Prints this usage message. -f/--force: Force a new proxy to be generated. -b/--batch: Do not ask for user input. -k/--kerberos: Also check kerberos ticket. -q/--quiet: Suppress regular output, errors still shown shown. Can only be used in batch mode.