Error Message 'ADD not allowed on DOCLINKS' appears when trying to add an attachment - IBM Maximo

When you get this message, it means user must have a default insert site within his user application profile.

BMXAA0024E - The action ADD is not allowed on object DOCLINKS. Verify the business rules for the object and define the appropriate action for the object

Goto > Security > Users

1. Select Default Insert Site

And you are done.