I have the same Problem. I checked the ports from my router. Checked the key (key from ea support) and reentered often, but nothing worked. Firwall is off, reinstalled often, this all didn't help.

I have the same error. My copy of the game was from Amazon UK. I've tried re-entering the correct key multiple times, but it continues to say that my serial code is invalid.

Is there any solution to this?

My key is entered correct, it works fine from ~17:00 till ~23:00 (GMT+2), but I can't play the rest of time - then the serial invalid message pops up. Maybe the keys are selled twice or the keys are given to more than one person from ea support? Or the servers blocking them for hell sake... Just want to play at any times!

Still can ONLY play with my serial at AFTERNOON till evening (~ 17:00 / GMT +2). All other times it says serial invalid... When will this be fixed or what is the problem (Patch 1.2 and also now with Patch 1.4 still got this misbehave)?<------

this , but in my situation i can play about 1,2 hours then after leaving one server to connect to a another it says key invalid , well i just figured it out that i have to wait 4,5 hours then i can play again -_- please fix o_O!!!!! I mean this is a huge annoying bug and i paid good money for this so come on....

Dear Crytec team ,

i had a 3 hour ea support discussion and we tried to figure it out to fix it...guess what it didnt worked. As the last solution the support offered me a another key and guess what...i doesnt work!!!!! I never ever had such problems witha game registration, there is somethign really wrong int he system, i give it tomorrow another try...mabye its like op said that ic an play only to specific hours of the day....im really disappointed

I've tried that several times with no luck PLEASE can you help us, so that we can play online again

Serial number is void (((((( When will correct? I can not play. Why I did the preorder for it?

i am also getting "invalid key" error.

Awesome!

I would try entering your numbers 3 ways

1) cut and paste if that dont work
2)use lowercase letters
3)manually enter it

I had a member use lowercase letters and he was in dunno if that was pure luck or a glitch

LOOOOOOL

Now i am in and i am getting the invalid key error when i try to join the server!!!!!

on your login screen inside crysis below your password do you see your cd posted in there? If not you should be able to enter it right there as well

I enter serial number with "-", without "-", capital/small letters. Created the new account. Helps nothing, writes - Serial number isn't valid.

Serial number is entered correctly, it works mostly at afternoon/evening but mostly not on other times (reentering the key will not help!!).... Mabye it has something to do with the dailight Really not funny, bought a game and cannot play.

Serial number is entered correctly, it works mostly at afternoon/evening but mostly not on other times (reentering the key will not help!!).... Mabye it has something to do with the dailight Really not funny, bought a game and cannot play.

Yeah, so much people noticed the same... the game works only 5 hours.. but today it isn't working anymore.. no time to play..

It is still NOT working.

Thank you, EA and Crytech!

Yesterday i was at the "server list" inside multiplayer and when i tried to join any of the rooms it would give me the invalid key error. Today, it won′t let me pass through Multiplayer-campaign-etc screen.

My problem is:
-I accedently hit the wrong key by typing in the serial code
-I can log on to my account
-But when I want to join a to a server it sais that my serial code is invalid.
What am I suppost to do?

crytek didn't fixed this problem, and it would not be fixed with the new patch.. so you guys having this problem can only to cry at yours 39.99 euros.

When will correct a problem with an input in network game - "The code is void. For game in a network mode the valid serial number is required"? I did the preorder only that to play in a multiplayer. So never also couldn't come into a network mode. The desire in general something was gone to buy the made Crytek

I could play last month and now with the "new" account i made because i couldn't use the gamesas account, it says i got an invalid key WHEN i try to join a server.