PikaNetwork

If it says /register password password when you are trying to do it then you need to repeat your password. For example "/register pikanetwork pikanetwork". But if it says "/login password" and you registered the account before you will need to make a password reset request on forums(https://pika-network.net/password-reset/). Also if it says "/login password" and you didn't register the account that means that someone else did and you need to find a different IGN(Username) to play with on Pika. If you need any more help you can join Pika Discord and ask for help in help-lobby.

i just typing all times /register "myprivatepw" "myprivatepw" and this chat come

That means that you have too many accounts registered and that you can't register another account.

but how i can play bro?

You have 14 accounts registered on Pika already?