Since day one, Bing has offered webmasters the ability to submit sitemaps URLs anonymous using a HTTP request
Despite its promise, recent evaluations have shown that it was often subject to misuse by spammers. As a result, we will be deprecating the ability for anonymous sitemap submissions starting today.
We continue to recommend having sitemaps containing all relevant URLs hosted on your web sites and refreshing those once per day. Trusted ways to inform search engines include:
Bing and other search engines will generally attempt to crawl known trusted submitted sitemaps at least once a day for changes.
Additionally, we encourage all webmasters to adopt https://www.indexnow.org to inform Bing and other search engines real time of latest content changes on their websites.
Principal Program Manager