There was an error adding a member to the marketing list. Error description: Failed to get list members (D365 Online)

I am getting the following error in my new online CRM. Does anybody know the solution?

Unhandled Exception: System.ServiceModel.FaultException`1[[Microsoft.Xrm.Sdk.OrganizationServiceFault, Microsoft.Xrm.Sdk, Version=9.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35]]: System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> Microsoft.Crm.CrmException: Failed to get list members instances count.
at Microsoft.Crm.Dialogs.AddToListDialogPage.ConfigureForm()
at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
at Microsoft.Crm.Application.Controls.AppPage.OnPreRender(EventArgs e)
at System.Web.UI.Control.PreRenderRecursiveInternal()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at ASP._grid_cmds_dlg_addtolist_aspx.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously): Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #35AAB26FDetail:
<OrganizationServiceFault xmlns:i="www.w3.org/.../XMLSchema-instance" xmlns="schemas.microsoft.com/.../Contracts">
<ActivityId>e3940173-3015-41a7-9933-1fb42be15c23</ActivityId>
<ErrorCode>-2147220970</ErrorCode>
<ErrorDetails xmlns:d2p1="schemas.datacontract.org/.../System.Collections.Generic" />
<Message>System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---&gt; Microsoft.Crm.CrmException: Failed to get list members instances count.
at Microsoft.Crm.Dialogs.AddToListDialogPage.ConfigureForm()
at Microsoft.Crm.Application.Controls.AppUIPage.OnPreRender(EventArgs e)
at Microsoft.Crm.Application.Controls.AppPage.OnPreRender(EventArgs e)
at System.Web.UI.Control.PreRenderRecursiveInternal()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.HandleError(Exception e)
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at ASP._grid_cmds_dlg_addtolist_aspx.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&amp; completedSynchronously): Microsoft Dynamics CRM has experienced an error. Reference number for administrators or support: #35AAB26F</Message>
<Timestamp>2017-12-25T07:51:15.935737Z</Timestamp>
<ExceptionRetriable>false</ExceptionRetriable>
<ExceptionSource i:nil="true" />
<InnerFault>
<ActivityId>e3940173-3015-41a7-9933-1fb42be15c23</ActivityId>
<ErrorCode>-2147220970</ErrorCode>
<ErrorDetails xmlns:d3p1="schemas.datacontract.org/.../System.Collections.Generic" />
<Message>Failed to get list members instances count.</Message>
<Timestamp>2017-12-25T07:51:15.935737Z</Timestamp>
<ExceptionRetriable>false</ExceptionRetriable>
<ExceptionSource i:nil="true" />
<InnerFault i:nil="true" />
<OriginalException i:nil="true" />
<TraceText>
[Microsoft.Dynamics.Marketing.Plugins: Microsoft.Dynamics.Marketing.Plugins.AddListMember]
[13dc3f69-4895-e611-80d5-00155d396604: Marketing.AddListMember]

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