!! Manager login not working anymore !!

Waking up this morning, login to the manager returns an error. Same thing on the front end login using login snippet. I tried all account, with matching usernames /passwords and authorizing. Ftp is still working.
I just cleared the cache, didn't change anything, but I have to say I really don't know how to handle that kind of issue.
Leaving my pc yesterday everything was running fine and I wasn't working on the login snippet nor the core.

EDIT:
I'm using ModX Revolution 2.0.8-PL
Server : 5.1.41-3ubuntu12.10
UTF8 Unicode
Apache 2.2.14
MySQL 5.1.41
PHP 5.2.9-1
Backend database admin phpMyAdmin 3.3.10
Browsing with Chrome under XP

Any help, asap, would be appreciated as this is kinda critical for me, thanks. [ed. note: duk3fy last edited this post 15 years ago.]

It would be useful if you describe your system settings.

Sorry, I just edited my post with my settings

browse through your FTP, download these:
apache's error_log file
modx error log: core/cache/logs/error.log

tell me what you get.

error_log
[Sun Oct 16 04:02:19 2011] [notice] Digest: generating secret for digest authentication ...
[Sun Oct 16 04:02:19 2011] [notice] Digest: done
[Sun Oct 16 04:02:19 2011] [notice] LDAP: Built with OpenLDAP LDAP SDK
[Sun Oct 16 04:02:19 2011] [notice] LDAP: SSL support unavailable
[Sun Oct 16 04:02:20 2011] [notice] mod_python: Creating 4 session mutexes based on 256 max processes and 0 max threads.
[Sun Oct 16 04:02:20 2011] [notice] Apache/2.0.52 (Red Hat) configured -- resuming normal operations

ssl_error_log
[Sun Oct 16 04:02:20 2011] [warn] RSA server certificate CommonName (CN) `localhost.localdomain' does NOT match server name!?

Nothing recorded since 2 days ... and the logs/ directory doesnt exist, maybe because I did clear the cache/ folder. It didnt recreates itself when trying to reconnect.

Tell me if you need anything else, I think so ...

You said

login to the manager returns an error

What error?

L'identifiant ou le mot de passe saisi est incorrect. Veuillez vérifier l'identifiant, entrer à nouveau le mot de passe, puis réessayer.
i.e The username or password entered are wrong. Please check, re-enter a valid password and try again.

But there's something strange : this doesnt show up each time I submit the login form, it happens like 1 time out of ten. Otherwise, it just doesn't output anything and it feels like the page just refreshed without having sent anything to the server.

Again, as I said, the login snippet to login to web user in the front end is also inneficient.

Ok I found a workaround by deleting the cookies, but it didn't gave me an explanation of the problem. Does it happen for you too ? I'm leaving a website under modx to client very soon and even if it happens only once a year they're not going to be that happy to be faced to that kind of issue.

So what's the trick ?

how do you set the snippet call for Login ?
About the inefficiency, which part do you mean?
You can try to submit an issue to the original author's github.