"Ninja" worked yesterday but not today.  Is there a new code, or was the "ninja" code just a one time good deal?  Entering "ninja" today got a message saying "code invalid," which suggests that there might be a valid code.

Seems pretty obvious the code was a one-time only deal... imagine that would work every day. 

Yup a clanmate posted this yesterday, unlucky for those that missed it!

Where do you announce promo codes ? I only found out because someone in the global chat talked aboutit.

In the news releases on this forum, on the discord, and in game under the news tab.

Hi, folks! There has been a technical issue with entering promo codes, due to which some players do not receive bonuses when entering a valid promocode.

We're in the progress of fixing it. Please, try entering a promo code later

Server was restarted to fix inactive codes, is anyone having joy with NINJA+ now?

NINJA worked for me yesterday, but NINJA+ was a no go even after restart

Code Ninja worked for me today but no champion, just multi battle token, 

500k silver, 6 energy pots and 1- 3 day exp boost. 🙁 

Thanks for the tip , not working for me unfortunately.

Why are these codes not mentioned?

Hm. Tried both NINJA again (used yesterday) and NINJA+, neither worked for me.

todays code is NINJA+

It seems to only work for half the people though, it did not work for me, but a bunch of my clanmates said it did work for them.

It works.  I hope that it doesn't turn out that you need this code to get the free legendary.  It would be nice if this company ever communicated ahead of time about things which are upcoming.  There is zero cost to open communication and it is a necessary part of relationship building in business and in life.