What is canonical error in SEO?

HI
the issue regarding the URL of the website like if the URL is http://www.mysite.com and its showing httt://myasite.com this can seen as canonical issue.

Mysite dot com is the best for checking the cononical issues.

Google can reach to your web page through different URLs, this may create a confusion of duplicate content for search engine. To avoid this, we choose a preferred path for the web page or say canonical path for the web page.
If you don’t set a preferred path this may raise canonical issues.

More about it here: http://googlewebmastercentral.blogsp...canonical.html

Because of development issues, server setting, encoding platforms, and even natural site sequence a site may have multiple version of a homepage, or even an entire site. Let’s say you upgraded your site from an html site to a php site. Many times in the intersect pages are left on the server and are crawlable to the robots. These present several issues. You may have the same content and the new page never gets indexed. Links back to you may be to diverse versions. To mention just two of the most serious issues.

Canonical error is process of opens websites with both versions such as www and without www version that is called canonical error. Example
Suppose your home page opens with both version just like http://www.abc.com and http://abc.com

If any of your page in your site is reachable from various addresses like
example.com
example.com/index.html

These type of problems are called canonical errors.

Thanks for all share your best answers... I got it

hmmm it nice.. i've found that my site is also facing the same problem..
any body of you plz tell me how to resolve this issue..

Google can reach to your web page through different URLs, this may create a confusion of duplicate content for search engine then its errer called canonical error.