Process error

Hi Guys 

A  user was updating an email address field on a record within CRM and got the following:

Looking at the plugin error message in the log file I get the below

PY3.CRM13.UoL.MandE.Extensions.Plugins.Contact.PostUpdateHandler.Execute

Principal user (Id=a605a8fc-f2f4-e611-80e4-001dd1b71e60, type=8) is missing prvReadcdi_unsubscribe privilege (Id=03d7fb7d-d2fd-435e-ba48-ad1a6985884a)

Any thoughts would be appreciated

Thanks in advance