@oliversimon I'm a little new to server management, so pardon me if the questions sound a little stupid, but here goes:
1) When you wrote "localhost.localdomain" and "localhost", those were as is, and not meant to be replaced with anything, correct?
2) my mail.log output showed the following:
"unable to qualify my domain name (pokemon-nyc1) -- using short name"
Does the solution you provided still apply?
3) In the hosts file, I have an existing entry for:
127.0.1.1 pokemon-nyc1 pokemon-nyc1
Am I correct in assuming that the "yourhostname" is, in this case, 'pokemon-nyc1' ? Should the new 127.0.0.1 line then replace the 127.0.1.1 line already existing in the system?