Google crawler bot cannot read sitemap file


I have two sites in Cloudflare and Google Search. Site A was set to permanent redirection to new site/domain B. Inside e Google search console i have submitted sitemap.xml file for both site A (old) and site B (new). Google reports it can read the old sitemap.xml but cannot read the new sitemap.xml, reports error “Sitemap could not be read, zero pages discovered”. Can this be due to Cloudflare bot policy for Google crawler bot? Can you recommend any other configuration aspects to check?