Hello Bashar,

Google is right because the max number of links of a sitemap is 50.000
If you have more links you have to split the big sitemap, JSitemap has the splitting feature.
This is explained in the PDF docs at the paragraph 'Sitemap splitting'

After that i advice to limit the content data source and submit also a dynamic sitemap for recent articles to help Google to index quickly new articles. This technique is explained in the PDF docs at the paragraph 'Manage dynamic + static sitemap'

Best regards

John