Can't Change Password
When I try to change my password, it makes me log in, which I do using my old password. Then it makes me authenticate it with a code it sends to my email, which I do. Then I get to the change password screen, enter my old password, my new password, and my new password again to confirm. But it won't let me save it because it says "incorrect password." I know it's not the incorrect password, because I just used it to log in.
Opaite Mbohovái (3)
Based on your question, a few things is needed to confirm first. 1. Are you sure you type the correct old password? You can type your old password on a notepad first, check it whether it is correct, then paste it into the password textbox. Take note that for security purposes, some website do not allow to paste text into the password textbox. 2. Is there more to the error message other than "incorrect password"? Usually websites provide a much detailed error message to explain what you have done wrong. Could you perhaps show a much detailed error message? Please provide more details so I can replicate the error on my client computer.
Moambuepyre
In case of issues try to login to the Firefox Account via this website.
I had the same problem. I had to disable Two-step authentication. Then the CHANGE PASSWORD form on accounts.firefox.com accepted my old password.