[Plugin: Google XML Sitemaps] Sitemap Size limit

I am attempting to update my sitemap, but it does not seem to like the new pages I have added over the past few days. There seems to be a limit of 120 entries on the sitemap. is this something that is standard?
How can i make this show all the pages from my site?

https://www.ads-software.com/extend/plugins/google-sitemap-generator/