Cannot access /wp-admin or any other page after upgrade to 3.0

Similar problem here. Upgraded a single site to WordPress 3 and enabled multi user. Everything works fine on the main site but I can’t get at the backend of any new sites I create – same symptom as csw11235 above – just keep getting bounced back to the login page.

I’ve created new users, recreated sites, hacked around with the tables and config files but still no luck. There must be a better way to debug this type of problem?

Aha! – found the answer (for me at least) here:

https://www.ads-software.com/support/topic/413901

Added this line to wp-config.php and can now access admin for other hosted sites.

define(‘COOKIE_DOMAIN’, $_SERVER[‘HTTP_HOST’]);

As an aside WordPress, this would be a good idea to document/fix. I’m guessing lots of people using WP 3.0 for multi site will be hosting multiple domains too.

I tried adding define(‘COOKIE_DOMAIN’, $_SERVER[‘HTTP_HOST’]);
Still not able to access any admin pages. This is messed up. I have deleted all plugins.

I wish someone would resolve this.

Too many redirects occurred trying to open “https://ASDFlkjh.com/wp-admin/upgrade.php?_wp_http_referer=%2Fwp-admin%2Fupgrade.php%3F_wp_http_referer%3D%252Fwp-admin%252Fupgrade.php%253F_wp_http_referer%253D%25252Fwp-admin%25252Fupgrade.php%25253F_wp_http_referer%25253D%2525252Fwp-admin%2525252Fupgrade.php%2525253F_wp_http_referer%2525253D%252525252Fwp-admin%252525252Fupgrade.php%252525253F_wp_http_referer%252525253D%25252525252Fwp-admin%25252525252Fupgrade.php%25252525253F_wp_http_referer%25252525253D%2525252525252Fwp-admin%2525252525252Fupgrade.php%2525252525253F_wp_http_referer%2525252525253D%252525252525252Fwp-admin%252525252525252Fupgrade.php%252525252525253F_wp_http_referer%252525252525253D%25252525252525252Fwp-admin%25252525252525252Fupgrade.php%25252525252525253F_wp_http_referer%25252525252525253D%2525252525252525252Fwp-admin%2525252525252525252Fupgrade.php%2525252525252525253F_wp_http_referer%2525252525252525253D%252525252525252525252Fwp-admin%252525252525252525252Fupgrade.php%252525252525252525253F_wp_http_referer%252525252525252525253D%25252525252525252525252Fwp-admin%25252525252525252525252Fupgrade.php%25252525252525252525253F_wp_http_referer%25252525252525252525253D%2525252525252525252525252Fwp-admin%2525252525252525252525252Fupgrade.php%2525252525252525252525253F_wp_http_referer%2525252525252525252525253D%252525252525252525252525252Fwp-admin%252525252525252525252525252Fupgrade.php%252525252525252525252525253F_wp_http_referer%252525252525252525252525253D%25252525252525252525252525252Fwp-admin%25252525252525252525252525252F”. This might occur if you open a page that is redirected to open another page which then is redirected to open the original page.

I have the same problem as Particle…

I tried deleted all the plugins, but still can’t login to the admin area…anyone with anymore ideas?

Getting pretty desperate here…

Thanks

I solve my problem, renaming plugins folder to plugins.hold, creating a new empty plugins folder and deleting this line from my wp-config.php:
define ('COOKIE_DOMAIN', 'www.mydomain.com');

HELP!

I’m having the exact problem now, after upgrading WP. Seems that some of you found the fix… but I’m reading the answers and cannot figure it out. I’m green at this. Does someone have th etime to give me a step-by step fix?

I’m getting desperate here… and feeling ignorant.

thank you

PLEASE HELP!

I found the wp-content/plugins, as mrmist advised, and renamed it something else, then created an empty plugin as isistimento did.

I could not find the line he deleted in my wp-config.php, so I didn’t delete anything.

Still not able to open admin page.

Any suggestion?

thanks