That's odd...
Are you sure you're not using multiple password on different websites?
In worst case reset the Revora password in the login panel and give it another try on the C&C: Online website.
As for myself, I use 4 different passwords depending on the website or platform I signed up on.
And yes, 2 of which are 16 characters or longer and I still remember those well without the need of hints or anything. X3
Just to be sure...
Revora Creative Network account
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Logging into C&C: Online website uses the username and password credentials from your Revora Creative Network account.
If you happen to have forgotten what the password was, click on "I've forgotten my password" and follow the instruction in your mail inbox(or spam).
Double check if the password works
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After changing the password, try to log in on Revora again to double check if the password is working as intended.
If it does, give it another try on the C&C: Online website. Login with the Revora Creative Network account details.
Successfully logged in?
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Then go to the following link, setup an server account and try to login with those login credentials in the game you want to play.
Let us know if the problem still remains unchanged.