The option Mark as solved is no longer available for end-users in the Help Center.
Must be on at least a Team plan.
The option for end-users to mark their tickets as solved under My Activities is only available under the following conditions:
- Ticket type cannot be "Problem", it must be a "Question", "Task" or "Incident".
- The ticket must be assigned to an agent.
If the ticket in question meets the above conditions, then it is possible that the code for this feature may have been removed as part of some custom coding.
To re-add the code, an admin must navigate to Help Center > Customize Design > Edit Theme > Request Page and re-add the default code (find the code attached):