Lead from Landing page. Process error - Failed to get the context for the background operation

Hello,

Maybe someone can give a solution or a hint how to resolve this situation.

We have several processes with starting signal 'Lead added'. Everything works fine when Lead is added manualy. But when Lead comes from Landing page processes are not started and we see following error in BusinessProcess.Log:

Error while running process [ebda75d0-3e3b-4cb9-ac04-2cc30f61d512] for Lead (Id: [071ded65-fe59-4641-b265-2f04c733b509])

System.InvalidOperationException: Failed to get the context for the background operation. For services without authorization it is necessary to call Terrasoft.Web.Common.SessionHelper.SpecifyWebOperationIdentity.

   at Terrasoft.Core.ServiceBus.BusUtils.CreateUserContext(String userName, String sessionId, Guid externalAccessId)

We have tried several solutions:

1. Disabled CSRF protection in web.confing

    

    and even

    

    

    This didn't help

2. Modified starting signal, setting 'Run following elements in the background'. This gave some results, but the process haven't got values from the Lead, so we have tried to add timer. But as there can be a lot of such processes, timer has crashed regulary, so processes were stayed in Running status forever. That's why we have refused to use timer.

3. Than we have created process in the Lead object on message LeadInserted calling usual Process with Lead.Id parameter. This actualy works on our environment, but still raise error 'Failed to get the context for the background operation' on Customer's environments.

So, there is probably some differences in configuration.

Do you have any ideas what this can be? Or any ideas for more workaround solutions?

Thank you!