New J4858C SFP modules can't add to trunk

[MarkJohns]

I just purchased a few brand new J4858C sfp fiber modules for an aruba 2920-48g switch and installed them in port 47 and 48.  When i try to run the command trunk 47,48 trk1 lacp i get the message "module not present for port or invalid port: 47-48"  when i run the command "show interfaces transeiver detail" on the switch and compare it to an identical switch in production all the details are identical.  Anyone have any thoughts?  Maybe they are bad modules?

[parnassus]

Apart considering that latest 4 ports are dual personality, what the show tech transceivers CLI command reports?

[Linkk]

Do you see light coming out of the SFP? 
What is the result of "show tech transceiver" and what does "show log -r" say a few seconds after you plugged in the SFPs?
Also, like Parnassus said, the last ports are dual identity, so they have the same port number and you can't use both copper and fibre ports.