SEO Crawl error

Getting the following SEO error when trying to re-crawl the sitemap:

Your SEO crawl has timed out due to an unknown error. Please try again or contact support.

The plugin is listing out 56 URL that needs to be added, when I try to add the URLs manually, it doesn't seem to make any difference, and re-crawling the Sitemap is giving the above error as mentioned.

Please advise what could be done to correct this.