A user has set up Activity types for use when editing or adding new Activities under the Interactions > Activities tabs on a Contact Record. Some of these Activity types have disappeared from the list. The user would like to know how these activity types were removed, and how they can be replaced.
If the above solution is not feasible, and you would like us to recreate them for you, chat with Support and reference this article. Please include the solution ID, and (if you have them available) the names of the activities that are missing from your list.