A website has more than 5000 404 Errors, is this a problem?
34130
Are penalties applied if you have too many 404 errors on your site?
102901
How to handle link rot and broken links?
55255
Blog sometimes losing pages due to picking up incorrect configuration
32237
Why I do get error 101? How is my DNS involved?
22095
How to prevent automatic redirection of 404 errors and "incorrect" URLs?
39786
How do I resolve a HTTP 414 "Request URI too long" error?
106317
Google reports 404 errors on URLs that haven't existed for six months and are no longer linked to on my site
48888
Regarding the high number of rejected migrations from Stack Overflow to Server Fault
52815
Misleading error message when questions list fails to load
25548
Page returns 404 with POST variables, but not without
30454
Is Site Traffic Data Gone for Good After Fixing Previous Bug?
138562
Internal Server Error - What Now?
66467
Is http://stackexchange.com/ down ?
149008
Concurrent requests limit exceeded - how to find the problematic code
111613
Weird Stack Exchange logo on 404 pages on high-resolution screens
18280
How many links (internal) is too many?
135410
Intermittently receiving maintenance errors on SE network-wide