Help! Indesign file blurry when saving as a Jpeg.

[Lyndsay24130315r6dz]

I am working on some ads for a website - the size of the file being 628 x 90px. Any time I try to export them, they come up completely blurry, however whenever I up the DPI setting, the physical size of the file becomes larger and is rejected by the website it will be advertised on. png's are saving similarly. I have not had this issue before.. I feel there might just be something simple I am missing? Thank you!