So my problem is if you try to go to /admin and log-in using an administrator credentials or even the default login set via the _config.php file, it returns the user to the login page without logging them in.

The url says Security/login?BackURL=/admin

I tried flushing cache, rebuilding database, turning dev mode on, etc. Tried manually visiting the admin by typing it in, but it just keeps returning you to the login page.

The only thing I changed recently was to add GD::set_default_quality(100); to the _config.php and even removing it doesn't fix the problem.

Hmmm, very strange!

What does it say on the screen? failed login? already logged in? nothing at all?

"Security/login?BackURL=/admin" --> this simple means that you are redirected back to do a login and when that has worked then you will get directed to admin.

Yea, when you get bumped back to the login page it doesn't display any error messages or alerts or anything like that.

I even checked error log files, nothing in them about this.

Does anybody have any suggestions? I'm still stumped.

Tried logging in via a direct url but that didn't work either.

Seems like a cookie or session issue, or something isn't logging me in.

You find a fix for this?
having exactly same problem.. getting redirected back to login.. no errors

Not yet, but I'm planning on doing another big push on this issue this week. I'll keep this thread updated of any fixes I find.

just thought I would bump this... Any ideas greatly appreciated.
I have put the site in dev mode .. done a dev/build
flushed templates etc

But still cannot login or force login. Any ideas?

From memory I did have the same problem, try:

1. Check your .htaccess file and make sure its all good and doesn't look weird mine looks like this

### SILVERSTRIPE START ###
<Files *.ss>
Order deny,allow
Deny from all
Allow from 127.0.0.1
</Files>

<Files web.config>
Order deny,allow
Deny from all
</Files>

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /

RewriteCond %{REQUEST_URI} ^(.*)$
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* sapphire/main.php?url=%1&%{QUERY_STRING} [L]
</IfModule>
### SILVERSTRIPE END ###

2. Make sure your not trying to login with any previous member session data.
3. put Security::setDefaultAdmin('admin','admin'); into your config file and try logging in
4. Remove all your themes included javascript and try that?

hmmm... I did figure this one. try the above and get back if it doesn't help

Cheers
J