If you have issues with logging in there is a solution that usually works.
At the bottom of the board you can click Delete Cookies which will clear just the board cookies on that device or browser.
Then you must login again and it should just work.
You may also see a message saying you have to answer the CAPTCHA question, but it's a really easy one. Just intended to confuse bots and you only need do it this once.
If your phone/browser normally logs you in it won't be filling that part in so will fail.
If there are still problems let us know via contact us etc and we'll sort it.