Unable to upload data

[xzn]

[ERROR] Market Board data upload failed:
System.Net.WebException: The remote server returned an error: (400) Bad Request.
   at System.Net.WebClient.UploadDataInternal(Uri address, String method, Byte[] data, WebRequest& request)
   at System.Net.WebClient.UploadString(Uri address, String method, String data)
   at Dalamud.Game.Network.Universalis.MarketBoardUploaders.UniversalisMarketBoardUploader.Upload(MarketBoardItemRequest request)
   at UniversalisCommon.PacketProcessor.ProcessMarketBoardOfferings(Byte[] message)

Not sure if it's a server issue or a plugin issue.