You may encounter this at the very first time when you try to login just accepting the cookies.
Please crosscheck and make sure you've entered the right email ID which is your Sign-up email address and your Explaindio Member account password. Try to login to your Explaindio Membership Account using the same credentials and make sure if you can log into your Member account.
If your credentials i.e. Email Address and Password is working for your Explaindio Member Account here: https://account.explaindio.com/in/member go back to your ScriptVocalizer Login page, remove /login from the URL and press Enter.
When your Login page loads up simply try logging in again. If you can't login at all after several tries, clear cache, delete cookies of your browser and try logging in again. You may also try a different browser.
NOTE: Please make sure you don't have a special character in your Explaindio Member Account Password. In case you have any special character. If you have any special character in your Password, please change your password, set a new password without any special characters and login with the new password without any special character.