When registering, says enter afore-mentioned characters, but the content is blank - so how do I register !?
Seems to be a bug in the captcha. What happens if you press the update button next to it?
Side note: SketchUp requires users to come up with bad passwords here. If you sign in using Google you are allowed to have a good password instead.
Can you check whether your browser has an ad-blocker that has rejected loading the captcha image? If so, then disable the ad-blocker temporarily.
Or maybe for some other reason (network timeout, or the great wall) the captcha did not arrive in your browser?
Side note: If you add a special character to a good password, it becomes a better bad password (?)
Nah, in practice it mostly leads to the password being made shorter to make it easier to remember, causing it to be much, much less secure.
(But not this one)
Maybe, fill in the first name, first!