Hi Nyamjargal Sharav,
It appears to me that you're missing overviews (or, they were not built correctly). In ArcGIS Pro or ArcMap, please add the mosaic dataset, select the area where you don't see images (overviews), then add selected rasters and overviews (in the Content pane > . Mosaic dataset> Selection > Add To Map). Now investigate the overview(s) (and, also the source image(s)). See if the overviews are built correctly. If not, investigate the source image (zoom in/out) and see the image is displayed at all zoom levels.
If the overviews were not created correctly, these two might possible reasons:
1. Bad internal pyramids (possible solution: fix pyramids and rebuild overviews)
2. During the building process something went wrong e.g. output location was not available (possible solution: rebuild overviews)
Also, a quick note about the geonet, please note geonet platform is for peer to peer help.It's not meant to get answers from Esri Support. If you do need help from Esri Support, here is contact info: Esri Support Contact Support
Thanks
Pavan
