If your command is:
$ ssh -p 1122 path/to/pemfile user@[hostip/hostname]
You will also face the same error
ssh: Could not resolve hostname [hostname]: nodename nor servname provided, or not known
when you miss the option -i /path/to/pemfile
of ssh
So Command should be:
$ ssh -p 1122 -i path/to/pemfile user@[hostip/hostname]