I have configured EXM in Sitecore 8.2.2 and successfully able to send Email Campaign with Sitecore admin access. But for the ECM Users I am getting below error. Same is working fine in one of our environment with similar access rights.
Any idea on below issue (Extract from Sitecore EXM log)
14176 15:25:11 ERROR Object reference not set to an instance of an object. Exception: System.NullReferenceException **Message: Object reference not set to an instance of an object. Source: Sitecore.EmailCampaign at Sitecore.Modules.EmailCampaign.Core.ItemUtilExt.GetCampaignGroupPath(String campaignGroup)** at Sitecore.EmailCampaign.Server.Controllers.Message.MessageController.Get(String messageId, String language)