Error: Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0.

[othello777]

I pasted my session_id (not sure if that's correct) and also tried not putting anything for the token, but nothing worked. the link I pasted was to the /posts page as I want to bulk download all content

Newtonsoft.Json.JsonReaderException: Unexpected character encountered while parsing value: <. Path '', line 0, position 0.
   at bool Newtonsoft.Json.JsonTextReader.ParseValue()
   at bool Newtonsoft.Json.JsonReader.ReadAndMoveToContent()
   at bool Newtonsoft.Json.JsonReader.ReadForType(JsonContract contract, bool hasConverter)
   at object Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, bool checkAdditionalContent)
   at object Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType)
   at object Newtonsoft.Json.JsonSerializer.Deserialize(JsonReader reader, Type objectType)
   at object Newtonsoft.Json.JsonConvert.DeserializeObject(string value, Type type, JsonSerializerSettings settings)
   at T Newtonsoft.Json.JsonConvert.DeserializeObject<T>(string value, JsonSerializerSettings settings)
   at void PatreonDownloader.Program.DownloadAllPosts(HttpClient client, List<PostPage> pages, string backupFile) in /mnt/data/Development/PatreonDownloader/PatreonDownloader/Program.cs:line 233
   at void PatreonDownloader.Program.Main(string[] args) in /mnt/data/Development/PatreonDownloader/PatreonDownloader/Program.cs:line 116