Business Proces Error when adding a contact to a marketing list

Hello all,

We recieve an error when we try to add a contact to a markeing list in CRM online. 

Any idea how we can fix this issue?

Regards,

Salar

Error log file:

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=8.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: System.Web.HttpUnhandledException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #58135D91Detail:
<OrganizationServiceFault xmlns:i="www.w3.org/.../XMLSchema-instance" xmlns="schemas.microsoft.com/.../Contracts">
<ErrorCode>-2147220970</ErrorCode>
<ErrorDetails xmlns:d2p1="schemas.datacontract.org/.../System.Collections.Generic" />
<Message>System.Web.HttpUnhandledException: Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #58135D91</Message>
<Timestamp>2016-08-10T13:08:45.1553466Z</Timestamp>
<InnerFault>
<ErrorCode>-2147220891</ErrorCode>
<ErrorDetails xmlns:d3p1="schemas.datacontract.org/.../System.Collections.Generic" />
<Message>Error in AddMemberList plugin, The remote server returned an error: (401) Unauthorized.Message:The remote server returned an error: (401) Unauthorized.Stack: at ClickDimensions.Crm.MsCrm2011Plugins.Common.ExecuteWithRetry[T](Func`1 action)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.PostRecipients(IOrganizationService service, ITracingService tracer, String url, List`1 entities)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.SendAddToListTriggerRequest(IOrganizationService service, ITracingService tracer, Guid listId, List`1 recipients)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.Execute(IServiceProvider serviceProvider) at ClickDimensions.Crm.MsCrm2011Plugins.Common.ExecuteWithRetry[T](Func`1 action)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.PostRecipients(IOrganizationService service, ITracingService tracer, String url, List`1 entities)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.SendAddToListTriggerRequest(IOrganizationService service, ITracingService tracer, Guid listId, List`1 recipients)
at ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin.Execute(IServiceProvider serviceProvider)CONTEXT INFORMATION: ----------
UserId: ec35af60-2494-4643-b59d-77dc572fcd11
OrganizationId: e99a4825-df93-4757-9b2e-c5c2262c1d6f
OrganizationName: org51cb1997
MessageName: AddMember
Stage: 40
Mode: 0
PrimaryEntityName: list
SecondaryEntityName: none
BusinessUnitId: d4ec2009-4aae-e411-80df-c4346bad6054
CorrelationId: 369ea840-c301-4216-9d25-e626fff78f6c
Depth: 1
InitiatingUserId: ec35af60-2494-4643-b59d-77dc572fcd11
IsExecutingOffline: False
IsInTransaction: True
IsolationMode: 2
Mode: 0
OperationCreatedOn: 8/10/2016 1:08:45 PM
OperationId: a2e28ca5-f1ee-48d4-b342-07d4416be663
PrimaryEntityId: 00000000-0000-0000-0000-000000000000
OwningExtension LogicalName: sdkmessageprocessingstep
OwningExtension Name: ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin: AddMember of list
OwningExtension Id: 7abd2cab-7e60-e111-b398-1cc1dee8ea01
SharedVariables:
InputParameters: ListId: cd45cb86-c233-e611-811e-3863bb35fde0; EntityId: 05e39e75-1b32-e611-8124-3863bb351f38;
OutputParameters: Id: 9d3daf90-fb5e-e611-80e4-5065f38ada71;
PreEntityImages:
PostEntityImages:
----------
</Message>
<Timestamp>2016-08-10T13:08:45.1553466Z</Timestamp>
<InnerFault i:nil="true" />
<TraceText>

[ClickDimensions.Crm.MsCrm2011Plugins: ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin]
[7abd2cab-7e60-e111-b398-1cc1dee8ea01: ClickDimensions.Crm.MsCrm2011Plugins.AddMemberListPlugin: AddMember of list]

listId:cd45cb86-c233-e611-811e-3863bb35fde0
recipients.Count &gt; 0
SendAddToListTriggerRequest: start
Entity Type:contact
PostRecipients: start
request string:&lt;MarketingMember xmlns:i="www.w3.org/.../XMLSchema-instance"&gt;&lt;IDs&gt;05e39e75-1b32-e611-8124-3863bb351f38&lt;/IDs&gt;&lt;/MarketingMember&gt;

</TraceText>
</InnerFault>
<TraceText i:nil="true" />
</OrganizationServiceFault>