None of the reported errors there currently seem to be valid. All of the links in those errors validate in various sitemap validators. The ones which were reported to have over 50,000 URLs all have 40,000 or less.@Chris D
The indexing has stopped and we have 7 errors now
Our SEO has tanked harder than it ever has in 25 years, after moving from VBulletin to Xenforo.
This has been the worst financial blow to our company ever
The developers who did our migration destroyed our website and SEO, please help.
Clearly you've applied the suggested fix above now, but when was that actually done? Are the errors still there? Are the sitemap URLs exhibiting the errors now different?