Incorrect CAPTCHA at new customer registration
Problem: Captcha error for new customer account
When a new customer in your Magento 2 store registers his account, he has to verify he is human by solving CAPTCHA. A customer can get a notification of invalid CAPTCHA, despite he solved the task correctly.
Invalid CAPTCHA problem explanation
The invalid CAPTCHA error message may occur in a Magento-based online store due to a software conflict with the Magento's CAPTCHA system. There can be lots of reasons for the conflict to occur, for example, it can be caused by a custom Magento theme that blocks some parts of the CAPTCHA winow. Therefore a customer is unable to do all steps required by CAPTCHA system, leading to the Invalid CAPTCHA message.
To alleviate the issue in bot protection system, consider disabling CAPTCHA in the Magento admin panel. Disable it whether it is a Magento 2 default CAPTCHA module or external solution. New customers will only be required to provide a user name and password in order to create an in-store account.
Disable Google ReCAPTCHA by navigating in your store admin to
Stores -> Settings -> Configuration -> Security. In the
Google reCAPTCHA Admin Panel and
Google reCAPTCHA Storefront disable the ReCAPTCHA for the backend and frontend of your store.
Alternatively, you can disable Magento CAPTCHA via command line interface. First, connect to your Magento server via SSH. Use the standard Linux commands to change the current folder in the ttterminal to the folder of your Magento installation. When you are in the correct folder, execute the following commands to disable admin and frontend CAPTCHA respectively:
php bin/magento config:set admin/captcha/enable 0
php bin/magento config:set customer/captcha/enable 0
Next, clear the Magento cache with commands:
php bin/magento cache:flush
php bin/magento cache:clean
If these procedures don't resolve your issue, you may need to investigate the problem by debugging CAPTCHA process which requires some developer experience.