docs: Add troubleshooting help for issue #42

wiki/Troubleshooting.md

@@ -6,9 +6,22 @@
   Failed to map file. open(/Users/foo/Downloads/trash) failed with error 13
   Failure processing application bundle.
   Couldn't memory map the bundle file for reading.
-  A fatal error occured while processing application bundle
+  A fatal error occurred while processing application bundle
   ```
 
   This cryptic message is actually a permissions error, likely because your executable does not have
   read permissions set. Simply run `chmod u+rx trash` to add read + execute permissions on the
   `trash` executable.
+
+* When communicating with Radarr or Sonarr, you get the following exception message:
+
+  > FlurlParsingException: Response could not be deserialized to JSON: `GET
+  > http://hostname:6767/api/v3/customformat?apikey=SNIP` --->
+  > Newtonsoft.Json.JsonSerializationException: Deserialized JSON type
+  > 'Newtonsoft.Json.Linq.JArray' is not compatible with expected type
+  > 'Newtonsoft.Json.Linq.JObject'. Path '', line 1, position 2.
+
+  This means your Base URL is missing from the URL you specified in the YAML. See issue [#42] for
+  more details.
+
+[#42]: https://github.com/rcdailey/trash-updater/issues/42