How Many Type Error Of SEO?

[Nicole]

I Dont know It's Right or Wrong Question But I Saw Some Error Like 403, 401,

[Ria]

Nicole

These type of errors 400, 401 - 404, 501 - 503, etc are supposed to be the HTTP status codes. Such a kind of responses occur when a request is been made to the server to access a page on your site. This specification occur when you're not able to get the response that you want.

You can find for several status code similarly, just try searching for it to get wider information.

This link may clarify such errors and the reason of occurrence:
http://www.w3.org/Protocols/HTTP/HTRESP.html

[Aditya]

SEO errors on your website will cause negative effects on your SEO (search-engine optimization). Most search-engine networks have unique requirements, and major search engines such as Google and Yahoo! require your website to function properly for it to list well in search results.

[Santosh]

four most important error in SEO

404 error- Respounds with an error
200 error- if a page is missing
302 error- if the page is missing, its replace with a temporary redirect
301 error- Redirectes error to either a custom error page.

[Krystyna Krieger]

403 is HTTP error. The request requires user authentication. The response MUST include a WWW-Authenticate header field containing a challenge applicable to the requested resource. The client MAY repeat the request with a suitable Authorization header field. If the request already included Authorization credentials, then the 401 response indicates that authorization has been refused for those credentials. If the 401 response contains the same challenge as the prior response, and the user agent has already attempted authentication at least once, then the user should be presented the entity that was given in the response, since that entity might include relevant diagnostic information. HTTP access authentication is explained in "HTTP Authentication: Basic and Digest Access Authentication"

[Jack]

There are many types of error In SEO Like.
404 - Responds with an error, but shows a custom page to help your visitors.
200 - If a page is missing, it's replaced with the custom error page.
302 - If the page is missing, it's replaced with a temporary redirect to a custom error page.
301 - Redirects errors to either a custom error page, or some other page in the site.
But According to me there are 7 critical error in SEO which gives the bad effect on on our Sites.
which are..
1)Lack of Product Description
2)Using Product Descriptions from Manufacturers
3)Lack of Product Reviews
4)Not Optimizing Product Pages Based on The Search Demand
5)Non-Unique Titles
6)Lack of “Speaking” Urls
7)A Lot of Duplicate Content