https://www.threetowners.net/forum/

If the board isn't accepting your password here's what to do:
Go to https://www.threetowners.net/forum and click log on. Under the log on box there are the words I forgot my password click on that, then enter your username and the email address. Almost immediately a new password will be sent to you. If you are having problems or no longer have the email address you joined with, contact me: hugh.mccallum@gmail.com

You can change that password to suit later by clicking on User Control Panel under your logged on user name.

Then click on Profile and then click Edit account setting.

Logged in today with the new password that was sent to me yesterday, then I followed the steps you mention above Hughie and that allowed me to change it back to my original one (easier to remember)
I then logged out then back in again using the original without any problems.