When artboard import to jpg, image not show

 I tried to import artboard to jpg or png m~~~~~any times, but image isn't showing ⬆️ this picture. Mockup problem is no..... Can it be like this when the artboard size is large? Size is about 1920x27000. And export to pdf, the artboard begins at midway in pdf. I'm nervous and angry,,,Please help me,,,,,,,,,,I do my best to deliver my problem to help me someone,,,,I'm not good at eng,,.....