Hi,
Thank you for contacting us!
Follow the next steps in order to deactivate (disable) WordPress plugin manually via FTP:
1) Download and install FTP client (for example, Filezilla).
2) Open FTP client and enter your FTP access credentials (host, username and password) to access files on your server.
3) Navigate to ‘yourwordpresswebsite/wp-content/plugins’ directory.
4) Disable Google Captcha plugin by renaming its folder ‘google-captcha-plugin’ to anything else(e.g. goocle-captcha-plugin1).
After you log in into your dashboard, rename the plugin folder back.
Please complete the following steps in order to detect the problem and find its solution:
1) Try to activate a standard WordPress theme for a while (Twenty Fourteen, Twenty Fifteen or Twenty Sixteen) and check if the problem remains.
2) Try to deactivate all of your plugins except Google Captcha and also check if the problem is still present. If it is not, activate the plugins one-by-one, meanwhile checking, after which plugin activation the problem appears again.
3) Provide your System status. Follow the next instruction – https://docs.google.com/document/d/1Wi2X8RdRGXk9kMszQy1xItJrpN0ncXgioH935MaBKtc
Please note, that you can check the login page work in new incognito(private) window. This way you will stay logged in in your main browser window.
Let us know about the results.
Sincerely,
BestWebSoft Support Team