I have been trying to reset my password but when I go to the page I am not able to put my old P/W and after putting a new P/W it goes blank and I get no P/W change pop up. I have logged in and out several times but still no luck.
This post may apply to you: https://forum-en.guildwars2.com/forum/support/account/Password-Reset-Forcing-Me-to-Quit-GW2/first#post1383079
But I think the best way for you to get help is to contact Support by filing a ticket through the “Ask a Question” tab on that linked page. They will be able to assist you.