[have] no business

to have no right to be in a certain place or do a certain thing

The idiom "have no business" originates from the idea of one's activities or involvement being considered inappropriate or unrelated to a particular situation or context. It is often used to suggest that someone lacks the authority, relevance, or justification to be engaged in a specific matter or action.

When the meeting topic was confidential financial matters, Sarah had no business being in the room.
John had no business interrupting the professor's lecture with his irrelevant questions.
It's not your project, so you have no business making decisions about it.
During the dispute between two neighbors, the third neighbor had no business taking sides and making it worse.
As an outsider, Mark had no business meddling in the family's personal matters and disagreements.