XF 1.2 Unable to login to DEV site

[Mouth]

I've had my 1.2 DEV site running for several weeks, readiness for migrating production site.

Suddenly, I'm no longer able to logon to the DEV site - either standard site or Admin CP

All caching within config.php is commented out. Also in config.php, debug is active/yes and enablelisteners is 0/no

Restarted php(fpm) and memcached just to be sure.

When logging-in to Admin CP, the XF logo animates to teh top of screen - so I know password is correct/accepted, but then returned back to the Admin CP login prompt. Similar scenario for main site login attempts.

Result is the same using both Chrome and Safari, Chrome also in Incognito mode. I've also removed all local browser cache/cookies, and restarted browser.

What step sure I try next?

 

[Jeremy]

Can you see any server error logs being logged? Do you have cookies enabled?

 

[Mouth]

Can you see any server error logs being logged? Do you have cookies enabled?

Nothing logged into either nginx or php logs.

Cookies active via config.php with

// Cookie support
$config['cookie'] = array(
'prefix' => 'dev.site_',
'path' => '/',
'domain' => 'dev.site.com'
);

 

[Jeremy]

Does the domain match your dev site?

 

[Mouth]

Does the domain match your dev site?

Yes.
I've commented the cookie section out of config.php and it now works. Nothing's changed though with config.php or domain/url since it was working fine. Thanks.