Server error (5xx)
What it means
The server failed while answering these URLs. Search engines drop pages that return 5xx repeatedly, and visitors see nothing at all.
How to fix it
Check the server's error log for the exact failure. A 500 is usually an application exception, a 502 or 504 an upstream or timeout problem, and a 503 either genuine overload or a maintenance page left switched on. Fix the cause, then recrawl to confirm. If a 503 is deliberate, send a Retry-After header so crawlers come back rather than dropping the page.
Finding it in CrawlStat
After a crawl, open Issues and pick Server error (5xx). Click Show all in Pages to filter the Pages table to the affected pages, or Export affected to hand the list to whoever owns the fix. Audit ID: status_5xx.