Admin login not working

Sometimes I could not login to admin area. The username and password is correct.
Not showing wrong password or username. But it is not happening in everytime. I transferred the files from local server to client server. Is there any session or cookie problem? But I implemented many other projects like this and they are working. If anyone have answer for this problem please help me as soon as possible.:(

I would be checking and re-checking the config files over and over. Also if you are using an SSL certificate, make sure it is properly setup and using the correct path. Also check with your provider to make sure they have not made any changes to their SSL server configs. Ours did that unannounced once and messed up us BIG time.

Good Luck...

0be1