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Call HTTP Web Service;  Exception details: System.FormatException: The header name format is invalid.

Question asked by henryoh on Jul 26, 2015
Latest reply on Feb 10, 2016 by janeyres

I was referencing “NWO365_calling_a_web_service.pdf” in a Nintex Workflow calling a web service.

I am able to access the web service with the REST client. Inputting the URI to access the service root URI, resource path and query string options without any issues. 


I use the Nintex Action: Call HTTP Web Service and it consistently throws an error

I assumed it needed permissions for Nintex Workflows, in Site Setting --> Site App  permission on the Office 365 site, permission was granted.

The initial Build dictionary processed fine but the error on the Call HTTP Web Service this persisted 5x time with little modification

{Workflow Context:Current item URL}/_api/web/lists/GetByTitle('Tutorial')/Items?$select=Title


RequestorId: 101048b2-a162-cb15-0000-000000000000. Details: An unhandled exception occurred during the execution of the workflow instance. Exception details: System.FormatException: The header name format is invalid. at System.Net.Http.Headers.HttpHeaders.CheckHeaderName(String name) at System.Net.Http.Headers.HttpHeaders.Add(String name, String value) at Microsoft.Activities.Messaging.SendHttpRequest.AddHeader(String headerName, DynamicItem headerValue, Boolean isContentHeader, HttpRequestMessage requestMessage, IList`1& contentHeaders, Boolean& isEmptyValue) at Microsoft.Activities.Messaging.SendHttpRequest.SendRequest(NativeActivityContext context) at System.Activities.NativeActivity.InternalExecute(ActivityInstance instance, ActivityExecutor executor, BookmarkManager bookmarkManager) at System.Activities.Runtime.ActivityExecutor.ExecuteActivityWorkItem.ExecuteBody(ActivityExecutor executor, BookmarkManager bookmarkManager, Location resultLocation) Exception from activity SendHttpRequest HttpGet Switch<String> Sequence Microsoft.SharePoint.WorkflowServices.Activities.CallHTTPWebService Sequence Flowchart Calling a Web Service.WorkflowXaml_8330f4d7_cded_47b2_bd46_e98608fd64dd


Please let me know your thoughts.



Call HTTP Web Service

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