Not an Issue Web request callback raised an exception (plugin error)

I see zero information in this to work off of. I have NFC what's going on. It just spams it over and over every few seconds.

Code:

Web request callback raised an exception (JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0.)   at Newtonsoft.Json.JsonTextReader.ParseValue () [0x00000] in <filename unknown>:0   at Newtonsoft.Json.JsonTextReader.Read () [0x00000] in <filename unknown>:0   at Newtonsoft.Json.JsonReader.ReadAndMoveToContent () [0x00000] in <filename unknown>:0   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadForType (Newtonsoft.Json.JsonReader reader, Newtonsoft.Json.Serialization.JsonContract contract, Boolean hasConverter) [0x00000] in <filename unknown>:0   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize (Newtonsoft.Json.JsonReader reader, System.Type objectType, Boolean checkAdditionalContent) [0x00000] in <filename unknown>:0