Why my registration is rejected, what should I do?
You need atleast 500 ADA in your wallet to be able to register to vote.
I have more than 500 ADA (all delegated)
Imo try another wallet like Typhon or Adalite.
and if you still have troubles id recommand asking here : Telegram: Contact @ProjectCatalystChat
How can I know if my registration is confirmed? can I check it somewhere?
The registration is opened?
Im not 100% sure as i didnt find a date and im not really into catalyst right now.