NAMD 2.11 precompiled binaries do not work. Please use NAMD 2.11 installed from the source and available via module namd/2.11.
The NAMD 2.11 issue involves changes to the command charmrun in Charmm++.
A typical symtom is:
Host key verification failed. Charmrun> Error 255 returned from remote shell (n72:0)
For more details see http://www.ks.uiuc.edu/Research/namd/mailing_list/namd-l.2016-2017/0039.html.
This has been resolved because Oakley has been retired.