If you are on the Spring Update 1 of CRM 2015 or later, if errors occur in the Plug-In, it is possible to view server side trace logs to help determine why errors may be occurring. To turn on preservation of trace logs, go to Settings>Administration>System Settings. On the Customization tab you may set "Enable logging to plug-in trace log" to
Setting the log to Exception would only preserve session logs on which errors occur.
After turning this setting on, you will be able to view preserved trace logs from Settings>Plug-In Trace Log.