@Ravi Kumar Dega , This is expected behavior while you are hosting a static website on Azure storage account. The blob endpoint serves data only for the index.html path and throws 404 errors whenever there is an unknown path in the URL. While refreshing there are chances of adding extra elements to the URL of the blob that causes the 404 error. There are two ways in which you can avoid this 404 error for unknown paths,
Replace Error document with Index.html,
or
Use Azure CDN rules engine concept for rewriting the source path to destination index.html,
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