Hello,
I'm new to game and just signed up today.
And I'm also facing the 500 Internal Error after captcha, and to just let you know that this is a bug in the captcha sine I use another site which uses this captcha and that site also gives this error. Also both your site and that site give error synchronously.

I'll strongly suggest to change the captcha service since it wastes a lot of time. In 5hrs that i've played I was barely able to buy a worker and a pickaxe while using the lake that is.

So please do change the service as soon as possible.