When things go wrong and huggle doesn't behave as it should, there is a fairly large toolkit that can be used to debug what is wrong.
Verbosity of program
Huggle can be started in so called "debug mode" in this mode, interface contains few buttons and menus that are normally hidden and display much more technical information that normally aren't visible. You can start huggle in verbose mode by passing it -v parameter where amount of v's is level of verbosity (for example -vv is verbosity level 2).
Huggle produces a system log, this log contains more information when in debug mode. It can be dumped out to a file using parameter --syslog <name of file>.
If you are reporting a bug or problem with huggle, this system log can be useful for developers in order to figure out what is wrong.
One of most effective ways to diagnose the issues. Enabling traffic dump using parameter --qd will generate output file that contains raw traffic sent by huggle and received from web servers. This file will be called querydump.dat and it will be located in a working directory from which Huggle was started. On Windows this path can be defined in shortcut properties. This file can be very huge even in very short time. It may contain sensitive information and it's recommended to examine it before sending to anyone untrusted.