XML sitemap is rendering as HTML

I'm using Jsitemap and SH404sef, and found that the XML sitemap was rendering as HTML rather than XML.
To fix this, go to the configuration options in SH404SEF, General > Advanced tabs and ensure that the setting '301 redirects from non-SEF to SEF' in the configuration of sh404sef is not enabled.

If you still experience issues after changing this setting you can also change the sh404sef settings: configuration > by component and choose 'Leave as non-sef' or 'Use Joomla router' for Jmap.

Additionally, within the Jsitemap settings Configuration > Advanced settings it's important to ensure that the following parameter is disabled and set to 'No' as by default in order to always use native raw links for each sitemap: