Hello all, could not directly find a related post with this solution from forums so announcing it now.
Many of us has had this issue when login to manager with valid credentials you simply get thrown back to login page. Cleared cache from browser, deleted cache/ directory contents and flushed the modx_session table and still no go. Trying with other browser and you fly in faster than you can say Revolution.
A simple solution that I hope will help to others also. Instead of trying to access the manager directly through manager/ try using other manager page. For example this takes you to your user profile page: manager/?a=76 . At this point it will ask for credentials, write in the username and password and login and you should be in. Only negative thing is that you always have to use other page than manager/ to login. This does not remove the issue from it.
Found this workaround just few moments ago when tried everything with the site and using Firefox to test it, did not have this problem in Chrome where flushing of the cache's etc... did help.
I hope this helps you all with same problem.
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