Why HTTP basic access authentication not working on Apple Safari 5.1?

after installing Safari 5.1 on Mac OS X Lion I found an interesting issue with the browsers. I found that it is not having expected behavior with HTTP basic access authentication as well as server page redirects. I was looking for username and password on the pages which are protected HTTP basic access authentication. Server is sending 301 or 302 header when redirected to that page.
There was no issue with any of the previous version of Safari or any other browser I was using.

I was suffering from the same issue and managed to resolve the same by doing below mentioned thing.

You should uncheck User names and passwords into Auto fill part of preferences file of Safari. now close safari.

After doing that I have relaunched Safari and checked User names and passwords options.

Once I have done it was returning to authentication page which was resulted into the user names and password which are returning to auto fill simplicity..

Could be below mentioned steps help?
First of all you should reset Safari and close Safari.

After that you should browse to Home/Library/Preferences

Over here you have to remove

Code:

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com.apple.Safari.plist
com.apple.Safari.RSS.plist

---

now go for Home/Library/Safari/ folder and remove

Code:

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history.plist
lastsession.plist

---

now browse to Home/Library/Caches/Metadata/Safari/ and simply remove the content folder.

Let me know whether above mentioned solution worked for you. if not then I think you will need to clear the cache of the browser.

• First of all close the browser if you have already opened.
• Now browse to ~/Library/Caches/com.apple.Safari/Cache.db and sent the Cache.db file to Trash.
• Once you have done relaunch the browser.

Look if any updates are available for the browser on the official website. After installing the updates you should relaunch the browser on the system.