The display of annotative objects is controlled by the current annotation scale of model space and the Annotation Scale property of a viewport. If you are in model space, make sure the Annotation Scale drop-down list on the status bar ( Find)shows the scale you want annotative objects to be displayed at.
For layout viewports, select the viewport and, on the status bar, click Viewport Scale Sync ( Find). The Viewport Scale property and the Annotation Scale property for the viewport take the same value.