Falls and does not release ip address

[slogger]

Falls with exception
Fatal Exception: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean java.lang.String.equalsIgnoreCase(java.lang.String)' on a null object reference
at com.rjfun.cordova.httpd.NanoHTTPD$HTTPSession.run(NanoHTTPD.java:430)
at java.lang.Thread.run(Thread.java:818)

If we go back to the app, then up server can no longer, because the ip address is busy (IO Exception: bind failed: EADDRINUSE)