Through years of spending time shut away in libraries and study chambers, trying to understand and memorise the lessons taught to you by your masters. While this has given you a great wealth of knowledge, it has meant that you haven't necessarily developed the skills your peers can rely on when interacting in different social situations.
When you attempt to learn or recall a piece of lore, if you do not know that information, you often know where and if your teachers will know it. Usually, this information comes from a library, scriptorium, university, or a sage or other learned person or creature. Your DM might rule that the knowledge you seek is secreted away in an almost inaccessible place, or that it simply cannot be found. Here your Dungeon Master might rule the knowledge which you seek is secreted away in an almost inaccessible place or simply it can not be found. Unearthing the deepest secrets of the multiverse able to require an adventure or even the whole campaign.