This is the exception from the SDK:
GroupDocs.Conversion.Cloud.Sdk.Client.ApiException:
The namespace declaration attribute has an incorrect ‘namespaceURI’: ‘A Namespace Name for xmlns Attributes’.
at GroupDocs.Conversion.Cloud.Sdk.Client.RequestHandlers.ApiExceptionRequestHandler.ThrowApiException(HttpWebResponse webResponse, Stream resultStream)
at GroupDocs.Conversion.Cloud.Sdk.Client.RequestHandlers.ApiExceptionRequestHandler.ProcessResponse(HttpWebResponse response, Stream resultStream)
at System.Collections.Generic.List1.ForEach(Action1 action)
at GroupDocs.Conversion.Cloud.Sdk.Client.ApiInvoker.ReadResponse(WebRequest client, Boolean binaryResponse)
at GroupDocs.Conversion.Cloud.Sdk.Client.ApiInvoker.InvokeInternal(String path, String method, Boolean binaryResponse, String body, Dictionary2 headerParams, Dictionary2 formParams, String contentType)
at GroupDocs.Conversion.Cloud.Sdk.Api.ConvertApi.ConvertDocument(ConvertDocumentRequest request)
This topic has been moved to the related forum: Error calling ConvertDocument - Free Support Forum - groupdocs.cloud