Generated Sitemap encounters Error

Good Day,

What is the possible reason I am encountering this error for the sitemap? How can I fix this one? Thank You in advance.

Please see screenshot in the link:
http://www.goodtimeharbourcruises.com.au/sitemap.xml
https://gyazo.com/bd6af51dc2bf79b09b7eebd5b9f363c5