Yeah what Spider said...
Tested on 10.11.1, Acrobat DC 2015.9.20077.160923.
Just tested the x32 bit and it is not working, so 10.9 upwards and Acrobat DC only, I won't be fixing the x32 part for Acrobat XI
What version OS X are you running?
I am a little bit perplexed as to why you are having issues. It seems like a networking issue, are you able to test the Windows Pitstop Pro on the licensing server, to check all that side is working and to narrow down the issue?
Also if you check out the logs in C:\Enfocus\bg_data_system_v010\flexlm.log and scroll down you should see the license checkout running something like:
7:58:03 (esko) OUT: "pspro_11" [email protected]
7:58:05 (esko) IN: "pspro_11" [email protected]
Maybe if you pm me your flexlm.log so I can see whats wrong.