Not good, it means the modules is not able to read back from facebook the subscriber data.
1. your provider blocked the file_get_contents when using facebook as destination url
2. facebook blocked your provider addresses
Actually I can send you a modified version of the module which log with more details the communication, but I expect them to be empty. The only solution is to change the way we are connection to facebook to really debug the communication.
I’ll send you the updated module to your email.
Stefano.