If I try to login to pokemonrevolution.net everything works, but when I try to login to the game client I get the error "Invalid Username or Password"  (both in silver and gold server). Any way to fix this?

Hi. Thank you for contacting us about your issue.
 

Is it possible maybe you forgot your password or username? In that case, I would invite you to our website to try and change your password to see if that was the issue. 
 

Here's the direct link: https://pokemonrevolution.net/forgot-password
 

If the issue happens to be that you forgot your username or your email, I would then invite to contact us again in the General Complaint tab of our Resolution Center in the Forum to make a thread and explain the situation.

Again, here is the link: https://pokemonrevolution.net/forum/forum/37-general-complaint-area/
 

Please keep in touch with us to know if changing your password was the solution. Looking forward to hearing back from you,
 

- Kubrick