I have faced the issue in Magento 2.2.5 version.  When I Place the order as a guest user, the “Create Account” button shows a blank error.

So, I resolved this issue using below steps:

First, you need to override vendor/magento/module- checkout/Block/Registration.php file in your any existing module.

To override this file:
Create new file ‘di.xml‘ at app/code/Vender/Modulename/etc/.

Add the following code in the newly created file.

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="MagentoCheckoutBlockRegistration" type="VenderModulenameBlockRegistration" />
</config>

Then create new file Registration.php at app/code/Vender/Modulename/Block/, then find below code and replace it with new code as mentioned below:

From:

/**
     * Retrieve account creation url
     *
     * @return string
     * @codeCoverageIgnore
     */
    public function getCreateAccountUrl()
    {
        return $this->getUrl('checkout/account/delegateCreate');
    }

To:

/**
     * Retrieve account creation url
     *
     * @return string
     * @codeCoverageIgnore
     */
    public function getCreateAccountUrl()
    {
        return $this->getUrl('checkout/account/create');
    }