2 problems with Wordpress, the main one constantly asks to enter a captcha and does not accept it, what should I do?

Question

CAPTCHA

Good time of the day! Guys, there are two problems:
1. There is a site on wordpress and there is a plugin for online booking. So, if you log in to the admin panel and go to the page with online booking, everything works correctly, but if you are not logged in to the admin panel, then there is a window with captcha and PPC.

And here is the error in the console:

But if you are authorized in the admin panel, then everything is OK and there are no errors in the console:

the following error is written in the hosting logs:
[Mon Mar 27 20:53:41 2017] [error] [client 93.73.221.117] PHP Notice: Undefined index: go in /usr/share/zakrito/index.php on line 9, referer: inlight.com.ua/book/?go=1&captcha=3067
2. For some reason, at some point, if you are authorized in the admin panel, it starts redirecting from any page to the main one. It is strange that if you go to the plugins in the admin panel, or edit the page ( inlight.com.ua/wp-admin/post.php), then everything is OK, and open a link like inlight.com.ua/book, then immediately redirect to inlight.com. ua/
Thank you for your attention and help.